Hello,

I've been having the problem where my stopping power is significantly lacking, so I went ahead and replaced the front rotors, calipers, and pads when I found slight cracking in my rotors. I haven't yet attempted to drive the car since bleeding the brakes and replacing the fronts but I've had suspicions that my rear brakes weren't doing anything at all to begin with.

For example, whenever I apply a heavy braking force (either quick or gradual) on gravel, the fronts lock up, but the rear wheels keep pushing through the brake. The lack of rear breaking power has almost pushed me into a busy intersection, so it's time to fix it.

When looking at the drums opened up, it looked like one of the cylinders wasn't functioning properly since one piston was pushed out and the other was flat in its bore. On top of that, one brake shoe appeared to have a bit more wear than the other. I am looking to replace these cylinders, but I have a few questions :

1) How big of a pain is it to remove the drum brake cylinders? (I know that drum brakes suck in general, but I've never had to remove the cylinder)

2) Are there any cylinders that perform better than OEM?

3) Are there any other upgrades that you can do to drums besides the rear-disc conversion? The only other one that I could think of was to use better brake shoes; I'm looking into using Stillen.

4) Another upgrade that I've seen is to change the proportioning valve spring. After restoring the rear drums, will I benefit from this? I've only seen this mentioned in rear-disc conversion articles, so I'm unsure if it will help if I retain the rear drums.

My plan is to eventually take this car through some autox courses and I feel that if I can restore the power that the front and rear brakes originally had then I should be better off than I am now. I was originally considering the rear-disc conversion, but the more research I did, the more it seemed like a hassle/money pit than what I would actually gain from it.

Any recommendations that you may have will be helpful.

Thanks

 

If you can get lucky and snag a disc brake rear from a junkyard it's worth the hassle.

As far as the cylinders go yes drum brakes are a pain, but if you are replacing shoes anyways once you have that much out its just one break line and two bolts and the cylinder pops out.

The only extra headache from changing cylinders is having to bleed the brakes again. But that's not really a big deal either.

If you plan to auto x then disc brakes might be worth the hassle, you will be putting a lot more wear on the brakes in a lot shorter time. You will greatly appreciate how much quicker you can change a rotor or pads versus rebuilding a drum setup again and again as shoes wear out.

Drum brakes aren't quite as bad as people make them out to be, and are perfectly adequate for anyone who just street drives, but are a pain if you do anything that will require more often shoe replacements.

 

the wheel cylinders in an F body aren't just "2 bolts" to remove... they have that ridiculous retaining clip that holds them in place... i've never actually tried to put one back in, but i have fought to take a couple out of cars i was junking out in the past..

one upgrade that the GN guys do to their rear drum brakes is to use a wheel cylinder for some S10 truck application. they use the same front and rear brakes as the third gen F body, but they had bigger pistons in them. i don't know the exact application or part numbers, but they do pop right in and it's something to look into..

 

You can replace the iron drums with lighter aluminum drums. Less rotational mass to try to stop.

The front brakes do the majority of stopping. If you get the rears to work too much, you just end up locking them under a hard stop.

 

Ah, I've never seen a clip on a wheel cylinder. I've always seen them bolted in. But I have not messed with them on a third gen, so it was just a guess. But still. I'd imagine a new cylinder come with a new clip?

 

Yes but he's still has issues if when he apply the brakes on anything less solid than pavement and it locks and pushes the front wheels. Mine did this but it turned out that the last person to change the shoes put some springs in wrong and it was catching and preventing the self adjuster from turning out like it should so my shoes wore to the point of not touching the drum anymore.

 

I see, so it seems like you gain more of a convenience factor when it comes to replacing them with disc with maybe a slight performance upgrade. I could look around for a rear end, but I live in Iowa and I haven't found a junk yard that even has a third gen. Plus I would have to rebuild the rear-end to retain my 4.10 gearing. If I can find one with discs I would seriously consider it.

I will research some more on s10 cylinders in a third gen. This seems like a useful upgrade along with better shoes, cleaned parts, and new (correctly installed) springs. I think that I will go along this path for now to see how it fares.

 

If you have a welder or a friend with one and can find a zr2 s10 rear that's disc brakes and 3.73 gears and can be made to fit our cars.

 

I have a ford 9" rear so my brakes are diff but my setup is...
Second gen F body backing plates, center hole enlarged to fit the ford axles/bearings
1978 Trans am wheel cylinders
Second gen F body auto zone brake shoes
Aluminum brake drums

Power Stop slotted front rotors
Auto Zone brake pads

Strange small bore manual brake master cylinder
No prop valve
10 # residual valve on rear brake line
TCI line lock on front brake line

 

fresh drum brakes can help a car stop a lot better if you dial them in properly...

but if you want to look at swapping to discs, look for a rearend out of a 98-02. it's a few inches wider overall, but is an easy bolt in. i got a smoking deal on a disc rear with 3.42 gears and a factory locker out of a 70,000 mile '02 Z28 that got hit in the front... i paid $300 for a rear end assembly that normally goes for about $700... never know, a local yard might have one and not even know what it's worth so you can get it cheap..

 

I love the Pick N Pull chain of yards, got a 9 bolt disc rear for $80 on a half off day.

 

I've read about doing this, I remember the article that I was reading stated that these are 2" wider for each wheel, so 4" total. Did you install this on your third gen? How does it look? Is 2" per wheel noticeable?

 

Does anybody have the p/n for the S10 wheel cylinders that will fit our cars? Or at least which years of the truck that cross reference to our car?

 

Before I redid my rear end, it had all sorts of issues... locked up when pulling out of a parked spot, 1 wheel locked up going around corners when wet and or even just slowing down in the rain, etc...

I bought all new parts from Rock Auto and hit it overhauled, and it's night and day better (I'm sure nothing much had been done since it was born in 91)...

I did upgrade to new steel braided hoses, new master cylinder / slave, and fluid, etc... but it all works great and like new... All of the previous problems I had are gone and it works like it's supposed to...

Not sure if the proportioning valve would do that much since the car originally came with drum rear, but if you change to disc rear, for sure get it...

 

If this is mostly a street/auto x car, you want to keep the stock wheel cylinder size which is 3/4" bore diameter. This size will have ample stopping power with properly set and rebuilt rear drum system.

A power brake S10 has the same exact wheel cylinder as the thirdgen f-body and the 1978-1987 G-body cars.

The mid 80s manual brake S10 wheel cylinders are the larger 7/8" bore diameter. I would only recommend the larger wheel cylinders if you are drag racing with large sticky rear tires. You will most likely get premature rear brake lockup if running the same size wheels and tires on all four corners and the larger 7/8" bore wheel cylinder.

Porterfield has a performance rear shoe in different compounds.

http://porterfield-brakes.com/index.php

If you don't have the right tools, the rear wheel cylinder replacement is a pain (at least is was for me).

I wouldn't change anything else in the system until you rebuild the rear drum brakes, adjust them correctly, and see how your car brakes. I don't think the spring change in the prop valve is for rear drum brakes. I think it only is good for rear disc brakes. There are two different types of prop valves for thirdgen f-bodies. Disc/drum and disc/disc. Disc/drum have a 10lb residual valve built in for the rear drum brakes. The 10lb residual valve is required and keeps some pressure in the rear brake line so the shoes don't back away from the drum too much. A disc/disc prop valve does not have this 10lb residual valve. If going to rear disc brakes, you will need to use a disc/disc prop valve. There are no new stock replacement prop valves you can buy. You can get a universal disc/disc prop valve, but you will most likely have to replumb your brake hard lines to install the universal disc/disc prop valve.

Braking wise, the only draw back to drum brakes is they can overheat. On the rear, it is not as much of an issue, but auto-x may overheat them. I would see how your rebuilt drum brakes work with auto-x before going to a rear disc brake system.

Yes drum brakes are ugly, but drum have more friction material than disc brake pad, they are self energizing, the wheel cylinder for drum brakes need less brake fluid volume than disc brakes calipers, and a drum brake setup is lighter than all stock rear disc systems. You can also buy aluminum replacement drums that can make them even lighter.

Self energizing means that the shoes want to naturally wedge themselves against the drum, so the brake effort for the driver much less.

This AMC guy "vented" his front and rear drum and he swears by it. This may be an option to help keep the rear drums cooler during auto-x.

http://worldpowersystems.com/AMC/196...merican/Drums/

Let me know if you have any additional questions.

 

Which tools would make things easier that are not a part of a standard tool box?

 

No tool that I know of, but here are some "techniques".

http://www.elcaminocentral.com/showthread.php?t=22939

 

Lisle 18800:



I don't think they make this anymore. I've seen it in other brands.

 

When I look that up it says that it is for X and J bodies. I've never done drum brakes on an F-body, so would that tool actually help?

 

So what are the best shoes out there? I have looked around but can't find anything other than the standard Raybestos type products. I know with disks there are a lot like Hawk's, EBC, etc. Is there anything that is a little better than Autozone specials for the rear drums?

 

http://porterfield-brakes.com/produc...productID=4022

 

Thanks.

 

there are alot of "tools" available for drum brakes. Most are gimmicky at best. Ive found a good stout pair of needle nosed pliers to be the best.
As previous posters have said, drums arent all that bad. If you rebuild them with new springs, wheel cylinder, and a good quality set of shoes, you might be suprised at how well they work.

 

Is the residual pressure valve red? Can you just pull this out for a drum to disc swap and run without it?

 

LOL No.

Do a job right, or don't do it at all.

 

Most of what I have read on here and talked with friends about says you can remove the valve and run without it when converting to disc.

 

That must be why GM took the time to design a separate valve for 4 wheel disc cars... You know, since they could just remove a piece and it'd work the same, it makes sense they'd invest the time into developing and manufacturing an unnecessary part. Makes perfect sense right?