Write-Up: Replacing rear rotors and pads. (lots of pics)

IF the e-brake is used, it's not a bad system, but how many people actually use theirs? Though, I do have to say I was pleased to see larger pads in the rear on the Riviera than commonly used on cars such as the Lumina and Grand Prix.

Yes, now if only they had put more meat into the FRONT brakes....

I agree, but it's easy enough to swap to a larger setup. It's really no worse than just about every other car in its segment. Unless you're looking at a Vette or something along those lines, I think just about most OE braking systems are undersized. IMHO.

Today you're probably right... I was spoiled by the 70's and 80's systems that I grew up on. Compared to the tiny hardware on this Rivi, my '69 Wildcat, '72 Cutlass, '73 Grand Am, and '81 Eldorado practically had oversized brakes

Oh I agree totally. I remember catching my front pads on fire in my 78' Z28 , replacing pads, turning rotors and good as new, doing that two or three times on a set of rotors. No such thing today. I agree totally, the old brake systems were much heavier duty

The E-brake in my '96 is frozen solid from years of not being used.

I just replaced my rear pads last Saturday without doing anything to the rotors and now the rotors warped.
With cars built in the past 15 years or so, I normally buy new rotors since they are so thin to begin with theses days I am hesitant to turn them.
This was a case of throw some pads on to buy time and stop the grinding that was just beginning.

Eldo wrote:

Today you're probably right... I was spoiled by the 70's and 80's systems that I grew up on. Compared to the tiny hardware on this Rivi, my '69 Wildcat, '72 Cutlass, '73 Grand Am, and '81 Eldorado practically had oversized brakes

Even though I had seen them before, I was still struck by how puny the rears on the '96 looked.

The last time I took a pair of the big front aluminum drums in to be turned, (the ones off my '70 Riv) a guy standing in line with me asked what kind of truck they were from.
He had a pair of drums in his hands from an import that looked like they would be inadequate for a lawn tractor.

Keep in mind, guys, the front brakes do 80% of the braking, and in '98 they stepped up to 12" rotors. You don't hear many guys with the newer brakes complaining about stopping power.

When you want to stop quicker, the key is bigger front discs, and a pad compound that is both sticky and usable into higher temperature ranges without fading. If you do the fronts correctly, the need to upgrade the rears (for stopping force) actually lessens because there's a lot more weight transferring to the front of the car. In a turn, you don't want the rear brakes stopping any harder than they do now.

The only reason I can think to beef up the rears is to deal with heat build-up on a road track or driving down mountain grades. But I would not want the rears to actually have any more braking force than they do stock. The 80/20 ratio factors in a margin of safely, while a 70/30 ratio could be dangerous. However a 90/10 situation really isn't such a bad thing when you really think about it.

Most cars up until the late 90's were 70/30 biased.

I'm not saying 70/30 is bad in every case (esp. RWD cars), but if you have a front-heavy FWD car like ours that is tuned for 80/20, you don't want to change that to 70/30, or esle the rear wheels could lock up easier in a turn, causing very bad loss of control. However, the main disadvantage of going 90/10 is the rears don't see quite as much work, which isn't a bad thing as long as the fronts can handle it.

I know what you're saying and I agree. I think the only time I would change brake bias would be if I had fully upgraded the ENTIRE braking system and was using a manual prop valve.

That's a good idea. It would be interesting to see just how much more rear you could dial in before the set-up becomes unstable. Right up to that point, you'd have a very quick-stopping Riv.

That's similar to what I did with my previous project. I completely removed the ABS, upgraded the fronts to larger rotors/calipers, went from drum to disc in the rear and used an adjustable prop valve. It would brake MUCH better and nearly put you through the windshield.

Ok guys, I'm helping my dad with his 99 Park Ave and we're stuck on step 6 of Matthews write up. I don't recall having this kind if trouble on my Riv. We have pryed and pulled but cannot get the caliper of the rotor, is it just a matter of really putting some strength behind it?

if both the bolts for the caliper are out (2) and the parking brake isnt on then it just takes some prying.
should be the same setup as the riv, but can you take a pic of where you are now?

The rears are hard to get off the rotor if it's old and worn down because there's a raised ridge around the outside of the disc. You can't push the piston in to open the pads without first taking the caliper off - it's a Catch 22 - so you have to force it.

Put two lug nuts finger tight on the rotor. Take out the 2 caliper mounting bolts, then insert a sturdy flat head driver between the top edge of the rotor and the inside edge of the caliper (between the pads). Pry at it until you can fit something bigger in, like the handle of a ratchet or a larger screw driver to pry further. Do the same from the bottom side. Eventually, you'll push the pads over the outside edge of the rotor, and it'll slide right off.

Remember, you'll need to turn in the piston a several turns if you're replacing with new pads and rotors. If you're only replacing rotors, it will need about 4-5 turns.

Thanks for the responses guys, got everything off and put back together and the cars stops great. My dads car has had some major shuddering. We figured it was the rear rotors since you could feel it in the pedal and not in the steering wheel. We took it apart after getting it off by simultaneously hammering on the top and bottom of the caliper bracket. So we found out that the culprit was the pads, which had separated from their base and were stuck to the rotor, thats what was preventing the caliper from coming off. We replaced the rotors aswell but perhaps the problem wasn't a warped rotor but loose and cracked pads.

Were the rear pads and rotors original equip? How many miles on them?

My dad can't quite remember when he last did the rear brakes. But he has done the fronts once between doing the rears last. They were definately not original. The cars got about 170km on it.

I think the rotor was warped, causing the judder. The cracked pads could be caused by hammering on the caliper to squeeze the pads over the ridge I was talking about on the outside of the rotor. Or the pads might have been poor quality. I've seen it happen on my wife's car. Glad you got it fixed!

The crack probably was caused by the hammering, but do you think it would have caused both sides of the pad to separate from its backing plate aswell? I can imaging braking with pads that are not stationary would caused some shudder, they were probably really cheap. We went with AC Delco for the pads and rotors now, front and back. Here are some picks...

Yes, it could have been due to the force needed to slip the pads over the outside ridge of the rotor. Best way to tell is to look at the rotor - when it's worn very thin, it makes the pads extremely hard to remove (like in your case). Hammering can cause the damage to the pads. Even if the pads did separate from the backing before removal, it wouldn't cause much problem as long as they didn't fall out of the caliper, and I find it hard to believe they could have stayed attached with that kind of damage.

Still, this shows why cheap pads are bad news!

I broke this bolt on the drivers side.

.

Right now I have zip ties holding it in place. I tried to drill the old bolt out and I also tried to use an easy out, but neither worked. Should I just drill a slightly larger hole and try to tap it or is the zip ties good enough. I know the correct answer is to retap the hole, but if the zip ties don't pose a threat then it would be an easier fix.

thats the e-brakecable. its allways better to have a safety feature secured . the cable and its housing are pretty stiff but there is a lot of movement back there so..probably good to drill and tap.

This is a great writeup!! Did the fronts yesterday and will be doing the rears soon when I pick up the piston tool for it.

Did the rears a few hours ago. The cube tool for the pistons definitely helped a lot. One of the pistons was giving me a little grief going back into the caliper but it did with enough turning.

Overall, the new pads make this car a lot better to drive. I used to get a "clink.. clink" sound going over really small sharp bumps in the road. The sound is gone. Can only assume it was attributed to pads being worn down quite far and had a little play. The car also seems to coast better. I feel that one of my fronts wasn't retracting all the way because it had to travel a drastic amount to make contact with the disc. I also used to get some odd vibration every now and then when I was on and off the brakes. Again, I'm starting to think it might have been a caliper not sliding properly.

So $38 worth of Raybestos pads from rockauto and $15 worth of misc other materials (piston tool, brake cleaner and lube) and you have a new set of pads on the car. Much better than whatever a local shop would charge.