modifying drum spindles for discs [Archive] - Chevelle Tech

: modifying drum spindles for discs


eduardo69chevelle
Mar 11th, 03, 12:47 PM
Between my son and I we currently have 4 68-72 Chevelles with front drum brakes. The cost of purchasing conversion kits is beyond reason and I saw in another posting that the modification of the drum spindles to accept the disc calipers is possible. The question is - are there drawings or details available to define the modification for a machinist? In addition, the first car has power brakes - would the master cylinder and/or proportioning valve need replaced as well?

BC
Mar 11th, 03, 3:04 PM
You can get a ton of info on David's page here: http://ourworld.compuserve.com/homepages/David_Pozzi/brakes.htm#Converting_Drums_to_Discs


But to make a long story short, yes, you will need a new MC when converting from drum to disks. It is possible to re-use your existing booster, just make sure the new MC matches the pushrod of the booster.

Good luck,
Bill C.

eduardo69chevelle
Mar 11th, 03, 4:16 PM
Thanks, there is valuable info there. My SS has disc brakes on the front so I can compare the spindles with the drums on the Malibu now that I know what I am looking for.

Professor_SS
Mar 11th, 03, 5:05 PM
Originally posted by eduardo69chevelle:
Thanks, there is valuable info there. My SS has disc brakes on the front so I can compare the spindles with the drums on the Malibu now that I know what I am looking for. I am interested in this info also for my up-coming 70 project. Please keep me posted on your findings. My 70 has power drums and I'd like to convert to 4 whell disks as economically as possible.

Slow66
Mar 11th, 03, 5:46 PM
They make kits that bolt up to the drum spindles. Wilwood, and aerospace components make a racing kit for the drum spindle. (I personally have the aerospace kit). As far as more street-type brakes, ECI makes a kit for $525 they can be seen thru www.ecihotrodbrakes.com (http://www.ecihotrodbrakes.com) . Hope that helped a bit.

FO_FDYFO
Mar 12th, 03, 8:41 AM
only 1 mod is needed to the spindles to convert them. mill the raised mounting surface (between the upper ball joint flange and the spindle) .593 inches lower that it already is. then the caliper brackets bolt right up. graemlins/thumbsup.gif

eduardo69chevelle
Mar 12th, 03, 9:08 AM
After modifying the spindles the calipers, bearings, rotors and master cylinder are common parts to get from about anywhere. Does anyone have suggestions about locating a proportioning valve and backing plates? I don't think these will be easy items to find in a junkyard without knowing all the cross-reference details. Is the proportioning valve a part that is likely to fail because I could not be certain once installed if it was working properly or not.

Peter F.
Mar 12th, 03, 11:03 PM
I hate to tell you, but the stock style caliper mounting brackets are available from Master Power www.mpbrakes.com (http://www.mpbrakes.com) but they're kind of pricy at $200 a pair.

Buy the proportioning valve for about $50 from GM. Try a mid 70's to 80's midsize application. A good parts guy can find it for you.

I drew a set in Autocad for my Impala and then had a local company laser them out of 3/8" steel. Cost was $30, Canadian $$ at that. I want to do the same for my Beaumont but won't until I get room to work on it so it will be a while. If you have any way to create a .dxf file of a bracket you can get them made yourself.

Long story, but MP pissed me off while I was doing the conversion.

Peter

FO_FDYFO
Mar 13th, 03, 8:15 AM
peter can you send me a copy of that file. i have every version of autocad. from one pete to another pete, thanks,
pete.lohr@apti.com

eduardo69chevelle
Mar 13th, 03, 12:45 PM
Pete - while you are sending the ACAD file, copy me on that also at eelston@atidayton.com. Is this the same as required for my Chevelle? Are these backing plates available from GM or a resto supplier?

Peter F.
Mar 13th, 03, 11:29 PM
eduardo

The only place I know of that makes and/or has the stock style brackets to fit the Chevelle spindles is Master Power for $200.

The bracket I made is Impala specific and you have to machine the big boss down somewhere around 1/2" for them. I used 65-82 Vette rotors and PU calipers but if I did it again I'd look at 3rd gen Camaro rotors.

Please don't take offense, but at this time I don't really want to give away my work to someone who could then manufacture and sell it for a profit themselves.

Look at this for some good ideas - http://www.chevytalk.com/tech/index.html

Peter

Cam Sweet
Mar 14th, 03, 8:44 AM
Our sponsor has aftermarket caliper mounting brackets for $109.
http://www.ss396.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=396&Product_Code=FM-2501&Category_Code=BRA-001

They also have a mini-kit which includes the brakets, dust shileds AND spindles for like $249. That's hard to beat!!!

Cam