Hello,

I am at the final stages of planning a 4 wheel disc brake conversion for my 1966 Chevelle. I have decided to go with the 12" x 1 1/4" Corvette rotor and 3/4 ton Suburban 2 7/8" caliper using a 'B' body spindle that has been very thoroughly covered in many previous posts. The other option is the Suburban JD7 caliper (3 5/32" piston) I will also install an adjustable proportioning valve. Originally for the rears I have looked at the 1993-1997 Camaro rear brake setup. The rear calipers has approximately a 1.6" diameter piston. I have looked into the rear setup of a 1995 Impala. That approximately has an piston diameter of 2 1/8". From the pictures I have seen and the info that I have read I think the Impala setup should bolt onto my 10 bolt rear end. I have driven an Impala and those brakes can stop a 4000+ lb car very effectively. I would prefer the Impala rear setup for 2 reasons. 1) The front to rear ratio would be consistent to what is on a stock Impala (74%) as the front calipers are also 2 7/8". 2) From what I figure, the Camaro set up with the smaller piston may not have enough pressure. I would prefer to go with a manual master cylinder for saving some room in the engine bay, but I think I will be stuck with a brake booster. If I were to go with a manual master cylinder which one do you think would be able to provide enough volume and still be able to be applied with a reasonable amount of pressure? My wife would like to drive the car on occasion and she only weighs about 115lbs so the brake pedal should be fairly light. If nothing works, I will be willing to go with a booster. I know transferring Camaro rear brakes has been tried with success. Has anyone tried or considered swapping in rear brakes from an Impala? Do you think I would I be better off using the 3 5/32" calipers instead of the 2 7/8" calipers? I know it would produce a lot more pressure, but would it be too much to compensate with the adjustable proportioning valve?

Thank you,

Kevin C

I'll try not to hijack your post, but I am interested too...

Does the Impala SS use an iron caliper? floating or fixed?

I have been thinking of the Cadillac/1978 TransAm rears, but I don't like the parking brake mechanism...

I think the master cylinder to use is a 68 Corvette Manual brake master, but not sure on the pedal effort...

Tony,

The Impala uses a PBR caliper that is very similar to a Camaro, except the piston diameter and the piston bore length is shorter. I have thought of the Corvette 1" manual master cyl and the required pressure and volume concerns me. The stock Impala uses a 1 1/4" bore power master cylinder. I have given more thought about the rotor. The rotor will not work due to a different bolt pattern. (5x5" vs 5x4.75")I am thinking of using rear rotors from an LT1 Camaro. From the pictures I have seen, they look like the same rotors other than the bolt pattern. There is the possibility of redrilling the Impala rotor.

Kevin C

Kevin, I don't think I have much of an answer for you, but I'm offering my assistence if you need pictures or measurements of the Impala SS rear brakes. I have a '94 Impala SS.

I'm using the 1 1/4" bore '68 Corvette 4-wheel disc power brake master cylinder (I'm not running a power brake booster). '70-76 Camaro front calipers and 1999 Ford Explorer rear calipers. Pedal effort is nearly the same as a my original 4-wheel manual drum setup. Maybe it'll be easier since your calipers will be different than what I have. I'm pretty sure your wife would have a tough time stopping the car if the pedal effort was like what I have right now.

Dirty,

Thank you for offering assistance! I'm glad you own an Impala! The guys at the parts store are getting tired of me going in to look at parts during my research. I quit doing that a few months ago. Considering you are using a 1 1/4" master cyl and you can still stop the car, do you think a 1" manual cylinder would provide enough fluid volume to fill those large calipers? Could you make a guess as to how much pressure you have to apply to stop the car? I may be wrong, but I think going from a 1 1/4" to a 1" master cylinder should decrease pedal pressure about about 36%. What is the diameter of the rear rotor on your Impala? Isn't the axle flange the same as what is on a Chevelle 10/12 bolt? I think a passenger car 10 bolt is a 10 bolt, and I think the flanges are the same from 1960's to 2004. How is the parking brake setup? I didn't see any calipers available online that have the parking brake included. Would you please post or e-mail some pictures of the rear brake assembly? What is the measurement from the axle center to the outer most point on the caliper? Thank you again so much for your help in advance.

Kevin C

I guess I'll throw in my 2 cents as I've done something similiar before...

First, I'd definitely recommend the JD7 calipers for the fronts... these will give you better pressure which will decrease the pedal pressure and you should not have any issues controlling the pressure front or rear. These calipers have the hose mounting point in the right place on top, but make sure you get the correct size METRIC banjo bolt to match the hoses you get. I would recommend regular Chevelle stock hoses or possibly some after-market braided ones to fit a Chevelle. I don't think you will need anything longer. These calipers also use the series '52' pads which I would recommend a good ceramic pad for...

For the MC, I'd go ahead and try the 68 Corvette manual 4-wheel disk one with the 1" bore. I tried this one and liked it, but it just didn't quite move enough fluid for my system. But I was using a rear disk system off a 77 Fleetwood which was one of the first versions that simply used a standard front caliper which the added ebrake, so the pistons were pretty big! You might find that with the Impala rear calipers being that big anf the larger front calipers, you might need to go with the larger bore 1 1/8" 68 corvette power MC, but without the booster. That is what I ended up with in the long run and it worked really good. Pedal feel was not bad at all and my wife could drive the car without complaining.

A couple of questions tho: First, are you sure the 95 Impala is a 5x5 bolt pattern? I thought they switched to the 5x4 3/4" long ago and was still that?? Second, the PRB style calipers do require a lot more line pressure than the single piston calipers, so you might find some issues there. I'd try to stay with the larger pistons in the rear if you can to help offset that problem. Otherwise, you might need the booster just to worj the back brakes!

Tony,
Have you thought about just getting the backing plates off the TA/Caddy and then just using the front calipers on the rears?? I'm sure you have seen 454's posts about his pinion-mounted parking brake system used in conjunction with the 'normal' calipers on the rear?? I can tell you that the rear calipers with the parking brake are very expensive whereas the normal ones are cheap! The cost difference will just about pay for one of those pinion mounted parking brake kits. Also, make sure you get your rear brake parts off a rear wheel drive car as the front wheel drive cars used a smaller backing plate that is real flimsy and small rear rotors. Stick with the large backing plates that use the smaller calipers.

Good luck,
Bill C.

Originally posted by BC:
I guess I'll throw in my 2 cents as I've done something similiar before...

First, I'd definitely recommend the JD7 calipers for the fronts...

...Stick with the large backing plates that use the smaller calipers.

Good luck,
Bill C. Yea, what he said.

I was about to post my reply and then Bill made all of my points and more and said it better than I could.

Thanks Bill. graemlins/thumbsup.gif

FYI Late model Caprice's have an 1 1/8" MC and the police version has a 1 1/4" MC. These aren't bolt in for our cars, but they can work with a little modification. I have a 1 1/4" that I am not using, if you need it let me know.

Tony,
Have you thought about just getting the backing plates off the TA/Caddy and then just using the
front calipers on the rears?? I'm sure you have seen 454's posts about his pinion-mounted parking
brake system used in conjunction with the 'normal' calipers on the rear?? I can tell you that the rear
calipers with the parking brake are very expensive whereas the normal ones are cheap! The cost
difference will just about pay for one of those pinion mounted parking brake kits. Also, make sure
you get your rear brake parts off a rear wheel drive car as the front wheel drive cars used a smaller
backing plate that is real flimsy and small rear rotors. Stick with the large backing plates that use
the smaller calipers. Thanks Bill,

Exactly what I was thinking. My backing plates are off a RWD Seville (I recall 1978 or 1979)... And FO_FDYFO's rear pinion brake was exactly what I was thinking about... But I didn't know what calipers to look for...

And the "core" Seville calipers I got definitely need to be rebuilt (and expensive)... And then theres the Parking brake cable issue... Mine's an early rearend (narrower), so I would need a much deeper notch in the shock mount than RJ did...

So for "rear" calipers, should I be looking for something like early A-body, etc, or are there better "Front" calipers to use on the rear?

Are the T/A rotors vented or solid? (I know the Seville used solid, so the caliper opening will be pretty narrow)... Anyone know of a vented rear rotor that will work?

I thought of trying to use the Vette rotors in the back too, but I am not sure I want to attempt modifying those backing plates to move the caliper out to clear the rotor... But maybe I'll give it a shot...

The fronts (using the Vette rotor and JD7 Suburban caliper) will still clear stock GM 15-inch ralleys, correct?


RJ,
Those late model masters... They're the aluminum (?) body with the plastic reservoir, correct? Will they work without a booster (push-rod hole deep enough?)? I want to run Manual brakes... I'll probably just run the 68 Vette power master...


I guess I should get off my @$$ and start working on this... The only big expense for me now is the front upper arms (no way to do DReinecke's work with my BB and headers, as the arms already hit with 1/2" of shims...).

Tony,

I believe the OD of the master cylinder is slightly larger that the hole on the Chevelle. Not a big problem. And they have a small hole not the deep. I have seen a very simple bracket made that will retain the pushrod. Either Joe, or Andrew B could likely answer this question better. If you want to keep the older cast iron look than the Vette MC is the way to go.

The TA rotors as far as I know are vented. They are basically the same as my Caddy rotors.

And Tony you have mail. ;)

Kevin,

First to answer BC's question on the bolt pattern. It's still 5x5.

The rear rotor is effectively 12" or 11 39/64" to be exact (per AC Delco's specs). It does have a 10-bolt rear-end (8.5") but I'll have to get back to you on the flange. Do you just want a measurement between bolt holes on the flange?

I don't have any pictures of the rear brakes, but I can crawl under there tonight and take some with my digital camera. The e-brake cable comes out towards the front and immediately bends around to ride along the axle tube (front of). I'll get pics and it'll make this super clear.

The e-brake cable has to be purchased separately. Gmpartsdirect pricing is anywhere from $30-$55 to your door depending on if you buy the cables with equalizer and connector. I'll look at what I have on my Impala to determine which parking brake cable is needed (GM lists more than a few).

For your axle measurement: Do you want from the center of the carrier housing to the outer most point on the caliper?? I think that's what you want.

I'll get under there tonight and do the detective work for you. Any thing else you need just ask. Oh, I also have a Year 2000 Part and Illustration Catalog of every part on the '91-96 B-body Chevrolets. It's too big to print (3000 pages), but I could print some pages and either fax or snail mail them to you. Like the rear end assembly would be good for you to have. Let me know.

First, I want to thank you all for your responses to my question.

BC... I agree that the 3 5/32" Caliper would be prefferable, but I am concerned with the balance front to rear, but I am willing to be wrong. I may have a misunderstanding as to how the adjustable proportioning valve works. Doesn't it restrict the pressure to the rear brakes? Fron what I understand, if the rear calipers cannot produce enough pressure in comparison to the fronts, then the valve would do no good. You mentioned about the Impala rear PBR calipers needing more pressure. The calipers are a single piston, 54mm (approx 2 1/8"). I could see the increased need for pressure if it was a multiple piston caliper. I had a question about the front flexible brake lines, but you already answered that. If I remember right from your previous posts, I think you have Caddy/TA rear brakes. I think that is a 2 1/2" piston caliper. I don't know if a 1" master cylinder would have enough volume to provide for the large front caliper and the 2 1/8" Impala calipers. I would rather have too much apply pressure, than have not enough pressure. I can always push harder, but if you run out of brake fluid, you're screwed. I think that I may be stuck with a brake booster and a 1 1/4" master cylinder. If you think I'm wrong please let me know. How much pressure do you think you have to apply to stop the car with your 1 1/8" master cylinder? I'm positive the Impala has a 5" x 5 bolt pattern. I checked into the 17" wheels for my car and they wouldn't work. graemlins/sad.gif

Airrj... Thank you for the offer of the Caprice master cyl, but I think I will definitely be using a 60's Corvette master cylinder, either manual or power, so I don't have to worry about machining the master cylinder.

Alan... The measurements between the axle housing flange holes would be great. I'm not going to ask you to take your Impala apart, but would you know of a website that would have a picture of the flange? If it does have an 8.5" axle housing, I can't immagine the flange would be different then what our Chevelle's have. Thank you in advance for the pictures. Would you also please take a picture of both sides. For the measurement I'm looking for, I'm not looking for the measurement from the carrier to the caliper. I'm looking for the measurement from the center of the axle end where the wheel mounts to the outer most point of the caliper. In effect I'm looking for a radius dimension of the caliper so I know the minumum inner diameter of the wheels that will fit. Would it be possible to e-mail me the pages of the catalog that are in reference to the rear brakes?

Thanks again,

Kevin C

Dang, that's a big rotor for the rear brakes of the Impala... most are only 11". The RWD Caddys and the TA used an 11" vented rotor, not solid, but make sure you have the correct backing plates. If you can find the link to Joe's web site, he has some pics I took comparing the two different backing plates. If you have the large backing plate that uses the smaller calipers, then you can simply use some calipers for an 80's or so camaro or whatever FRONT calipers. These should be smaller than the stock Chevelle ones and you will know when you see them. Again, Joe's site might have pics of those also. Please remember, my rear disks from a 77 Fleetwood were an early design that used a large caliper in the rears... they were the same size as the front calipers, only they added the ebrake. These took too much fluid. Sounds like the Imp ones are a little smaller and don't require as much fluid, but I think you might have to try the 1" bore MC to be sure. I know the power one would work, but pedal pressure goes up. My brakes actually felt better than any stock manual brake set up I've ever tried... not quite to power brake pressures, but I liked the feel much better.

Tony,
yes, the 12" Corvette rotors and JD7 calipers fit fine under 15" rims!

Kevin,
With the Imp calipers being single piston, I think the 1" bore MC would be preferable because of the increased pressure it will create. I'm betting that it will be enough fluid for those brakes, but trial and prayer will be the only way to know for sure. You are correct on the operation of the prop valve and if you don't have enough pressure, it won't do a thing!

One other thing you might look into and search for is in using a manual MC from an S-10. These are supposedly a quick-take-up design designed to move a bunch of fluid first, then use the regular smaller piston to build pressure. David Pozzi's web site has info on this I think!!

I'll check back... gotta go feed the mob!

Bill C.

Just a bit of quick trivia on the 94-96 Impala's (from Motor Trend's review back in 1994): Curb weight of 4218 lbs., 0-60 in 7.1 seconds, 60-0 in 120 feet. I've heard BMW 740i's of the time couldn't even match the Imp's braking performance. Back to the topic smile.gif

My findings from crawling around tonight:

Axle center to top of caliper: 7" . Now, I must say I had a hard time measuring this, but I believe the distance to be 6 3/4" to 7". That means the radius deminsion would be a max of 14".

Axle flange bolt hole spacing: I took two measurements - both were center of bolt to center of other bolt. So I guess that would in effect be center of hole to center of other hole. Measure: 1) Horizontal across top was 3.125"; 2) Vertical from top bolt to bottom bolt was 2.375". I'll clarify tomorrow with the pictures I took (my connection at home is SLOOOOW).

Pass side e-brake cable runs from the backing plate rearward, along the axle housing (rear of) to the drivers' side and loops to the outside of the driver's rear coil spring. It then jets towards the front of the car and connects in a junction with the Driver side e-brake cable. The driver side cable simply attaches to the backing plate and runs forward to connect in the previously mentioned junction with the pass side cable. I have a picture of this.

I took a lot of pics. Kevin, are you on DSL or cable modem? I could send them all or I will pick what I think show what you wanted pics of. Let me know. It was dark and I didn't have a lot of light, so they didn't come out super nice.

I guess that's about it for my update for now. I hope this data is useful. I'm sure at least the pics will be.

i took the rear disc off my 94 9C1 Caprice, due to the caliper guide pins seizing up after being replaced with new GM parts 2 summers ago- something to watch if the car gets driven a lot. i put on the drums off a 92 9C1 i parted out, and now the car stops again, and no pesky guide pins to seize up every 20,000 miles.
i am pondering using the Caprice setup on my Nova using a 98 and newer Z28/trans Am rotor. the parking brake is inside the rotor- think of a mini drum brake. rotors measure about 11.5" across by MAYBE 3/4"thick- they are vented and have a 5X5 bolt pattern with a larger pilot hole in the middle. the backing plate mounting pattern is the same as every Chevy passenger car from the 60's up- except for Vettes, and most low-perf 78-88 A and G bodies.
overall, it is a very light setup- i'd say the whole setup on one side weighs less than just a brake drum itself. if not for the silly guide pin design, it would be an awesome setup- since it was engineered to haul 4200 pound cars down from 100+ mph chasing perps on the interstate. a 3000-3500 pound car just being driven nice won't even give them a workout.

Thank you again for all of your answers. It just dawned on me what a bad a$$ brake system this could be. I will cost a lot less $$$ than buying a kit. In a few years when my family moves to Northern Arizona I should have no problem slowing down on the mountains going South leaving Flagstaff!

BC… I think I should try with the 1” manual master cylinder. If it doesn’t work out, I can always sell it on EBAY. Would you know of a way to calculate the fluid volume required for calipers and master cylinders. The S-10 master cylinder is interesting. Isn’t there fitment problems with the S-10 master cylinder? I’m not sure, but I do remember hearing something about a fit issue. Doesn’t a quick take up master cylinder need to work with quick take up calipers? I’m sure the Suburban calipers aren’t. How much pressure would you estimate you have to apply to the brake pedal to stop your car with the 1 1/8" MC?

Alan… Thanks for the measurements! I think the rear brakes will be very tight, but it should fit inside my 15” wheels. I may be wrong, but I think that is the same wheel fitment dimension for the front Corvette/Suburban caliper. I’m looking at new wheels eventually. I’ll probably go with 16” and possibly 17” if I can get a good price. I’ll have to check later today on my lunch brake, but I think the axle flange measurements are the same as on our Chevelles. Aren’t the Impala rear rotors vented? From what I remember they were. Funny how I can’t find a picture of one now. At work I’m on a T-1 line, so getting the pictures won’t be a problem. I’ll e-mail you my work address. If it’s not too much trouble I would like all of the pictures you took. One last dimension I would like is the dimension from the outer face of the axle housing flange to the surface that the wheel mounts up to. That should tell me how far my wheels will be moved out.

Novaderrik…I used to work as a technician for Chevrolet and I do remember the design problem around the guide pins on the rear calipers. What we did to fix it was to polish the pins with very fine emery cloth and coat the pins with anti seize compound, and then install them. Pretty much every brake job you did replace the pins. Just make sure the rubber boots are in good condition. I like the thought of having the parking brake inside the rotor. It’s a lot easier to deal with, especially with cable routing and wheel clearance. My father-in-law is a tool & die maker and I know he should have the ability to re-drill the rotors to fit the 4-3/4 x 5 bolt pattern. Thanks for the specs on the rotors, that is nice to know.

Thanks again. You guys are awesome! graemlins/beers.gif

Kevin C

I sent those pics Kevin, and it looks they worked for you. Good deal. Fitting these brakes into a 15" wheel is going to be tough. Hopefully it works for you. I doubt they'd fit in my 15" Weld Draglite wheels. The 11" rear Ford Explorer brakes I have on my Chevelle BARELY fit in the Draglites.

The parts catalog I have is in PDF (Adobe Reader) format. I've found I can copy/paste the data into Word and it looks good. When I'm done transferring the data I'll send you the Word file. You could almost buy everything from GM (although pricy), but I did notice the RH backing plate is dicontinued (typical GM - dicontinue one side and not the other :rolleyes: ).

The rear Impala rotors ARE vented. As for the slide pin design. It sucks and the Impala owners know all to well about it. I've driven nearly 40k miles since I bought mine and grease the pins every so often - I've been lucky so far. There is one guy who is milling these pins in Stainless Steel. I can't find his website now. I'll dig some more and post back.

I'll try and get your latest measurement done tonight or this weekend. Will that work for you? I know what you're looking for.

kevin,
Unfortunately, I have no idea how to measure the fluid transfer stuff and would have no idea how to figure it out. Have you checked out David's page at: http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm

been a while since I've looked at it, but it has a lot of info including some s10 mc info. Check the CBB (Cheap Big Brakes) web pages for more on this conversion and such. I do know you can use the quick take up type MC without special calipers.

I also have no idea what the pressure requirement is to stop the car... somewhere between the power setup I used to have, but not near as hard as a 'regular' factory manual setup. That's about the best I can do!

Hope that helps,
Bill C.

Alan,

Thanks for the pictures. They were of every angle possible. Exactly what I was looking for and then some. Thanks especially for the pictures of the brake line and e-brake routing. If anyone else would like some pictures, I can forward them on if Alan wouldn't mind. Any time you can get the measurement would be fine with me. No big rush. Thanks again for going through all of the trouble.

BC... I'll have to research the fluid volume. I know the formula to figure out the volume. (Diameter squared x 3.14 x height or distance traveled) I just have to figure out how far the master cylinder pistons move. I'll check Dave's website later this weekend.

I think I made up my mind for what I am going to do. I will do the 'B' body spindles, Corvette front rotors, 3 5/32" Suburban calipers, a rear Impala brake setup, adjustable proportioning valve, The master cylinder is still up in the air, but I am getting close. It will be a while before I get all of the parts together. I'm buying parts little by little to keep the wife happy, that way I won't get the F.F.L.F. (female fun limitation factor), and I will post when I get it done and keep you posted how its going together.

Thanks again for all of your help. graemlins/beers.gif
Kevin C

how are you planning on getting the Vette rotors onto the B body spindles? the B body has the old school single piece hub/rotor, and the Vette has a rotor that slips over the hub. i know someone around here made an old B body rotor into a hub by machining the rotor part off, but that seems like a bunch of screwing around to me. it would be easier to use the stock Chevelle spindle (top boss machined down on a drum spindle, or a spacer in the top hole on a disc spindle) with a drum brake hub turned down ever so slightly to fit inside the rotor. make a simple bracket to mount the caliper, and you are there.

Kevin,
If you want, I could check out the boxes in my garage and see what I have for stock out there?!

I probably have a very slightly used Corvette 1" MC amoung others. Also, I think I have several others if you want me to look. Might save a buck or two if you can use them.

Bill C.

Hello,

Novaderrik...I agree that it would be easier to reuse the stock spindle and make a caliper bracket. I know this has been discussed to death, and I don't want to start another fight with the benefits and disadvantages of the tall spindle conversion, I think the advantages more than outweigh the disadvantages with the 'B' body spindle. My father in law is a tool and die maker and he can take that rotor apart pretty easily.

BC... Let me know what you find for master cylinders, I'll probably be interested in buying one.

Thanks again,

Kevin C

Kevin,
I found several of them... which one did you decide to try??

Bill C.