Ever since I bought my 87 Civic HB 1.5 the brakes have been weak. They're not fading, but I can barely get the wheels to lock up even on a wet road.
The rotors and pads, the back cylinders, shoes and the master cylinder have all been replaced. The drums were turned(?) also. (The vacuum booster is in good shape.)
One shop said they tested the pressure at each wheel's bleed screw and the front brakes are getting good pressure, but the rear brakes aren't. They suggested replacing the proportioning valve.
Another shop has never heard of the valve ever going bad.
The fluid is basically new (after replacing the MC.)

Thanks for your help.

 

What size wheels are you running? If you have larger than stock wheels the brakes may not be able to overcome the greater mechanical forces the bigger diameter of the wheels are generating....

 

They are actually the stock wheels. The car is entirely stock.

 

I have never seen a bad proprtioning valve on a honda- I have seen one that leaked. However there is a first for everything. You might investigate the rear "pressure" problem. Are your rear shoes adjusted properly? You need to check your front caliper slides- they might be frozen or your caliper pistons may be binding. Also- don't go using generic auto parts store brake pads and shoes- Honda pads will give you the most grab in stock trim. (under normal driving)


[Modified by fixhondas, 6:19 PM 4/16/2002]

 

The rest of the braking system is in great condition. It took them an hour's worth of work to say it was the proportioning valve.
The front (new- 12k mi) rotors are starting to warp already because the back brakes aren't working as hard as they should.
Possibly a dumb question, but could a proportioning valve leak internally? I'm not losing any fluid.

 

yes it could leak internally- but both channels at the same time would be unlikely. The front left and right rear are one channel and the front right and rear left are another.

 

Could the valve be clogged in some way?
I didn't think it was the proportioning valve, either, but what else could it be?
I've also been told that the brake lines themselves are in good shape.

Please help.

 

what does your pedal feel like?

 

"Sluggish. Like a wet sponge."
-Airplane!

The pedal gets firmer with the engine off as I pump the brakes. It drops when I start the engine. It doesn't get any firmer if I pump it with the engine running.


[Modified by scn095, 10:51 AM 4/18/2002]

 

try this- while driving- pull the parking brake up some- not enough to lock up the wheels- then apply your brakes. How does the pedal feel?

 

Thanks for the idea. I'll give it a try.

 

It didn't do much, if anything at all to the feel of the pedal.
I could definately tell that the back brakes don't seem to be doing any work at all.
When I had the e-brake handle pulled up and pushed the pedal, the stopping power about equalled other cars that I have driven.
I don't really want to get a brake overhaul (less the MC and rear cylinders, of course), but if I have to do that to fix the problem, then what other option do I have?

 

Try to adjust your rear shoes- if the car felt half way decent with the parking brake pulled. You may have a valving problem (although it would be my last guess)I would have a good mechanic that works primarily on hondas drive it. They might be able to lead you in the right direction. Who did all of the brake work, which parts did you use?

 

sounds like you need to bleed the brakes some more, you probably still have trapped air in the lines.

 

Make sure the hard lines aren't corroded or kinked, or clogged.
Also, the brakes in these cars plain suck. My 86 is similar, and is as good as it will ever be.

 

I stopped by a local yard and picked up a proportioning valve and bought new drums at Napa and had them and new honda shoe kits put on. The drums from Napa were crap, so I took them back and had the original drums honed. Little, if any change. The guy who swapped the P-valve power-bled the brakes.
I replaced the carpeting in the car and saw that the hard lines that travel by the door sills are fine. If the brakes are made to be this weak than this sucks. I don't think that they were made that weak, so I will have to keep looking.