Reoccuring rear caliper failures. Any upgrades available?

[backinblack]

Hi there. My wife's 94 GP coupe has a real bad habit of chewing up rear rotors and seizing caliper sliders. I've changed out the rear end 3 times in the last 26k miles. I do know that there are underlying design flaws with the 92-94 cars (or so I've heard...), but how are the rears with the 96's? We've had the parking brake cable disconnected for quite some time, hoping that would prolong the life of the rear brakes in the event that the cables and actuators were causing this, but I drove her car the other day, and both rears locked up good on me, smoking the rotors and even melting the plastic lug caps. I have suspicions that there may be a problem with the proportioning valve not relaxing the rear lines. Any thoughts an/or constructive suggestions? Thanks

[GnatGoSplat]

94-96 are the same, and 88-93 are the same.

You've already got the updated rear calipers.

 

The proportioning valve is built into the master cylinder, so I'm not sure you can replace it. I would check to make sure the sliders are good and lubed. Also make sure the piston can rotate in without too much trouble. Other than that, I'm not too sure what else to try since you already have the improved calipers.

 

BTW, what is that rust on? That's really bad! :shock:

[backinblack]

Why, that would be the rockers on my '97! I was told by Pontiac that it was "normal wear and tear" for my car. Sure. Whatever... (That's a photo of the GOOD side if you'll believe that...!)

[GP1138]

Why, that would be the rockers on my '97! I was told by Pontiac that it was "normal wear and tear" for my car. Sure. Whatever... (That's a photo of the GOOD side if you'll believe that...!)

 

WTF? Did you ever WASH it?

[maybe2fast]

wow :shock:

[19Cutlass94]

if thats the good side then your car must be hurtin!

[94CutlassSLCoupe]

Where do you live? remind me not to move there!!! lol wow that's a lotta rust

[1990lumina]

I've seen worse, shit happens...comes for driving a car through less then ideal conditions in winter...I know after one year of winter for my car the paint is looking like shit compared to last fall, and there is fust starting all over the damn car :x ,

[Darkness]

When I worked at a GM dealership as a service writer long, long ago, we got a tech bulletin in about the GP rear calipers, since we were replacing rotors like crazy. According to the bulletin, the only way the rear calipers get adjusted is by applying the emergency brake and releasing it normally. Apparently there is some kind of cone in the caliper adjustment that works only off of the mechanical brake application. Otherwise, as you use your pads and they wear away, the calipers don't adjust and you get rusty rotors and caliper parts after a while, leading to very premature failer.

 

Use your emergency brake at least once a week and your problem should disappear.

[1990lumina]

Maybe that's why I never have brake dust on my rear wheels...the fronts are ALWAYS coated with heavy brake dust, howveer the rear never has any dust on them...I never use my e-brake..myself my rear calipers are seized...oh well, I'll drive it till everything starts shaking and front pads wear out and replace everything at once..

 

- Jeff L.

[z34_nut]

thats on a 97 prix!?

 

Anyway back on topic. A common problem I found out with replacing calipers is napa, or autozone, or who ever usually likes to send you aluminum sliders...

 

This is one of the more common problems with freezing calipers (aftermarket anyway). Aluminum expands and contracts at different rates, and eventually siezes due to abnormal wear.

 

Make sure they arn't aluminum, if they are, get them replaced, got to the service desk at napa or w/e and ask specifically for stainless steel, chrome plated sliders

[backinblack]

Why would you chrome plate sst sliders? When the plating flakes off, you'll still bind up...

 

BTW, as for the 97... I used to wash the car daily. No amount of washing will fix the fact that the rust starts on the inside of the rocker, where moisture sits and cannot escape. 2 strikes against me: 1. The car was part of a rental fleet in NJ and 2. The previous owners lived on a dirt road. Wet mud would sit in the fenders and rockers for a long time, eating away at the steel.

[GutlessSupreme]

Maybe that's why I never have brake dust on my rear wheels...the fronts are ALWAYS coated with heavy brake dust, howveer the rear never has any dust on them...I never use my e-brake

 

Nah, there's just less dust on the rears anyway because they're not used as hard. I literally use my parking brake EVERY time I park somewhere (and I have an auto tranny), and the front wheels are still coated while the rears are fairly clean.

 

Some probably think it's an odd habit.. but I never liked the feeling of the car rolling forward or backward half a foot after I put it in park and let my foot off the brake. Just never seemed all that great on the transmission.

[GP1138]

Some probably think it's an odd habit.. but I never liked the feeling of the car rolling forward or backward half a foot after I put it in park and let my foot off the brake. Just never seemed all that great on the transmission.

 

I HATE THAT TOO... I've actually had the car slide backwards on snow-covered driveways during blizzards. It was fucking annoying.