I also have weak brakes in the rear, when I looked at them recently. I just put a new master cylinder (rebuilt) in. I bench bled the master cylinder and then I flushed out the entire brake system and got rid of all the old fluid. (car has been sitting for awhile). But the rear brakes have always been weak, they will not stop (but will slow down the wheels) when the car is raised and in gear. I have noticed that the pin for the emergency brake at the caliper is missing on the drivers side. This pin pushes on the caliper when the emergency brake is used. This wouldn't affect the rear discs would it? How can I tell if I need new calipers or a proportioning valve? Also does anybody know what the pin is called and if it can be purchased separately?
Darrell

 

most of the braking happens in the front of the car. although it sounds like the prop valve in yours is getting weak or something because it should as least stop them from spinning

 

The missing pin won't affect the regular rear brake operation. I would suspect the rear lines are possibly clogged up or getting there, wearing out. How old are the rear lines? Also, I have extra pins that you are missing on hand, LMK if you'd like to get one.

Ed

 

Thanks Ed, the whole system is crystal clear and was just flushed. The fluid in the system is all new. I replaced the master cylinder and flushed the whole system. The rear brakes have always been like this as fas as I know. I bought the car in 1995 from the original owner. None of the lines had any difference in them when I flushed the brake lines. I always thought that it was close to the way they were suppose to operate.
Darrell

 

on mine they will lock up before the front ones will (although my rear s a bit light lol) so you should be getting more stopping bower out of them.. if they were drum brakes that would be an easy adjustment. but on the discs i am at a loss

 

If you can't use your ebrake, then you can't adjust the rear calipers properly.. Since they are a ratchet type caliper, the ebrake is required to properly adjust the distance the pads 'rest' from the rotor... Too much gap and the pads won't put enough pressure on the rotor, causing weak brakes...

 

and that makes since... sorta like the star gear for the drums..

 

exactly

 

Sorry but you're wrong. His car is a '91. All cars '90 and up got PBR rear brake calipers which do NOT use a ratchet mechanism in the caliper, the older style of rear discs did use an internal style of adjuster but not the better PBR style rear discs. There are adjustments that he can still make though. Read through these:

https://www.thirdgen.org/forums/brak...and+adjustment

and

https://www.thirdgen.org/forums/susp...ee+%252Btravel

and

https://www.thirdgen.org/forums/susp...ee+%252Btravel


Ed

 

Ahh, my bad... I forgot about the PBR calipers.

 

Hey guys, thanks for the info ed. I read those posts and also some others in a search. Now is there any way to tell for sure if the calipers need a rebuild kit. Also the e-brake free travel screw on the caliper is that only for setting the e-brake or is it also like an adjustment for the rear calipers and pads. I know the prop valve mod is not suppose to be done with the PBR brakes, does anybody know why. (curious) Or is there anyway to tell if it is your proportioning valve. Now I know that there is plenty of fluid coming out of the rears when bled, same amount as the fronts and the fronts work great. But like most other people here my rear brakes will not hold the tires in the rear when in gear and in the air. I guess I am looking for more certainty with which parts to test and to replace as needed
Darrell.

 

Replace the proportioning valve with a new one. Or better yet....heave the god awefull piece of junk and put in an adjustable unit, such as a WilWood. You simply will not BELIEVE the difference in braking performance. How to available in our Tech Articles.

A good set of pads such as Bendix Titanium also helps ( Front and rear ).

 

I have a full set of Wagner ThermoQuiets to put on. I may go that way. Just trying to fix the parts that are not working properly. Don't just want to throw money on new stuff that is not broke because I have to get my tranny rebuilt so the car can come out.

Darrell

 

The free travel adjustment will also align the pads parallel to the rotor, helping to provide even pad wear and proper pad engagement when you do pull the e-brake. First thing to look at when deciding to rebuild the calipers is seal appearance, if they look rough or are hard and not flexible, rebuild them. The kits are only $8-10 for each caliper.

Ed

 

Thanks Ed, I will try the rebuild kit first then I guess if that doesn't do it I will try the Wilwood valve or something. Out of curiosity what is the part# for the wilwood piece.

Darrell

 

I have no idea, I have never used one. Stock combo valves works great for me.

Ed

 

Well it looks like I may have to get some reman. calipers. I went to a few places and nobody has the rebuild kit listed for the rears. Some places do not have it in there systems.

 

thats not terribly uncommon.. I can go to just about every auto parts place in my area and none of them carry a single holley product... it is all "special order" if they can even find the thing. Same with parts for the car... "Hello, i would like a fuel sending unit", them -> " what year? , me-> "83' camaro" , them-> "That will be $500 for the intank fuel sending unit with the fuel pump". me-> "What do you mean fuiel pump.. mine is mechanical.. not intank..... how much for the one without the fuel pump attached", them-> "sorry there is no such thing", me-> "Bull^%^$, i have on in the car right now that is not working so we know the exists... guess i will go somewhere else that is more helpful"