[burnt clutch]

This is a silly question, but here goes; - I am going to convert my '68 Cutlass from 4 wheel drum to front disc brakes. I'm wondering how much less effective it would be to go manual brakes v.s. power assist? Is there any advantage of one over the other? As it sits the already has the power assist booster.
-Karl

[Aceshigh]

I've got a 70 442 Clone myself that has factory power disc fronts and drum rear.
My new 12 Bolt Chevy I'm putting in it in the next few weeks has 11" disc rears tho.
So I'll be full disc.

My .02 and from what I've been told,
For the Manual VS Power debate.
#1. Unless you're doing road racing and you want the FEEL of the pedal for braking and cornering, for a street driven car it's going to be a step up to go to power brakes.
#2. You're not going to have a heart attack stomping on the pedal trying to avoid an accident too.

For the Disc VS Drum debate

#1. Easier Maintenance with Disc VS Drum
#2. No worries of them failing on a few HARD brake instances consecutively with Disc.
#3. Performance of Disc is better then Drum.
#4. All modern cars on the road use front discs and ALOT use rear disc too.

So if you have ALOT of money tied up on your car you don't want to be subpar in the playing field IMO.

[rkd]

For my toy cars, the 66 included, I prefer manual brakes. The new manual front disc conversion seems to stop pretty nicely, even if it takes a bit more foot. No disadvantage in normal driving that I notice.

I like the idea of less stuff under the hood, and less stuff to have to repair, etc.

Although it is going to change soon, the present cam does not have enough vacuum to run a booster.

[burnt clutch]

I'm definatley going ahead with the upgrade to disk, my only gripe with power assist is that its not much of a help if you're trying to stop the car if the engine is dead, but that is such a remote scenario. I like the idea of no vacuum booster to play with and having one less thing to break...thanks for your feed back so far.
-Karl

[Keith Tedford]

All of our vehicles are disc brake. The truck is manual disc. About the only difference is that with the truck you have to push a little harder. Anyone who couldn't stop that truck probably isn't physically fit enough to drive any way.

[GenPac]

I am running manual disc/drum -- works better than my previous power setup with 5.5" vacuum, that's for damn sure.

[clintstl]

I am looking at discs for a chevy II and possibly a chevelle. My only reason for considering non power is what I have heard from folks on here..that is that it is one less thing to repair.

I put miles on classic cars...no trailer queens. I am also wondering how these disc conversions hold up under daily use. Anyone put a lot of miles a disc conversion?

[CHELKAMINO]

Originally Posted by clintstl

I put miles on classic cars...no trailer queens. I am also wondering how these disc conversions hold up under daily use. Anyone put a lot of miles a disc conversion?

I have put countless miles and many autocross passes on my 4 wheel disc upgrade. Mine are from a 2000 LS 1 Camaro though, not aftermarket.

[Georgia69]

If the question is, do you need power assist with disc brakes, I think the answer is yes, you do.

I've driven cars with non-power drums, and it was fine, but disc brakes appear to require more line pressure. I converted my 71 Nova to non-power front discs years ago, and I quickly grew to despise it. Pedal effort was WAY too high.

[TXCR13]

My personal experience with using manual front disc brakes is from conversions I did on a '55 Chevy a few years back and on my '66 300. I also will be doing one soon on my '46 Stude.

Neither manual system required a whole lot of pressure to stop the car normally, or to lock up the brakes. Yes, a little more effort than power assisted brakes is required, but any 6 year old has enough leg power to use power brakes, so it isn't like night and day on the pedal effort required IF the system has the right parts.

My other reason for going with manual disc up front is to get rid of that huge, unsightly, space-robbing, engine bay cluttering, vacuum leak causing brake booster. Personally can't stand them, but this is from someone who owns a driver, not a super nice correctly restored car. If I had one of those, I would restore it as is supposed to be.

[1966_L78]

Originally Posted by TXCR13

Neither manual system required a whole lot of pressure to stop the car normally, or to lock up the brakes. Yes, a little more effort than power assisted brakes is required, but any 6 year old has enough leg power to use power brakes, so it isn't like night and day on the pedal effort required IF the system has the right parts.

My other reason for going with manual disc up front is to get rid of that huge, unsightly, space-robbing, engine bay cluttering, vacuum leak causing brake booster. Personally can't stand them, but this is from someone who owns a driver, not a super nice correctly restored car. If I had one of those, I would restore it as is supposed to be.

I converted from power discs to manual discs (both with rear drums), and no significant difference in pedal effort... A little more effort but thats it...

It was a switch from stock "Chevelle" discs to C5 Corvette discs...


Just removing the ugly booster made the swap worthwhile...

[72ragtop]

Since you already have a booster, power seems like a no brainer to me. All depends what you're used to I guess, but pretty much all new cars come with power brakes for a reason, and it's not because they cost more.

[BlueSS454]

I have driven cars with all configurations..manual drum, power drum, power disc, and disc with no vacuum assist. The WORST one was disc with no assist. My 69 Malibu had manual drums and they worked just fine, but I changed it out for a spare power disc setup I just happen to have laying around because power disc is better.
My 69 Cutlass has power drum brakes on it. They work OK too, never had any issues with fading but it's still nowhere near as good as power disc.
Now having said that, the reason I believe disc brakes are difficult to apply when you lose vacuum is the fact that you are pushing 2 things, the master cylinder (requires little effort) and the power brake booster which has a giant diaphragm in it which compresses air (requires a lot more effort). The air has no where to go against the check valve so it makes applying the brakes in a loss of vacuum situation very difficult. The odds of that happening are slim, but it does happen. The question is do you want to worry about that 2% chance over having better brakes? I say no.
Truthfully all you need to do is get the correct master cylinder, proportioning valve that mounts under them master cylinder, and brake lines to do the conversion. You can modify your existing spindles to accept the dust shields and caliper brackets for the disc setup (you can get new). Buy some rotors, calipers, brake hoses, new bearings & seals and you can be on your way. If you don't want to change your brake hose brackets on the frame, get hoses for a 69 Camaro with disc brakes. Those brackets are different for drum vs. disc brake cars.