I started the original thread in the brake section back in January.
https://honda-tech.com/forums/suspension-brakes-54/no-rear-brakes-2477848/

It has had several suggestions but the problem is still there So I figured I would try it here.

Heres the details
1990 accord DX-non ABS, 280,000 miles, No pressure to rear wheels
Ice, snow, or gravel it will lock the fronts with relative ease, but absolutley will not lock the rears regardless of pedal pressure.
Brake pedal is high and solid, No air in system, new rear shoes, drums resurfaced. Wheel cylinders move when brake pedal is pressed with the drums off. E-brake works very well, The prop valve is a diagonal split type with one front and one rear running off each half of the MC so that rules out a bad MC. It seems like it got progressivley worse over the last year. I have been master certified for 10 years and currently work in a GM dealership on cars 10 times more complex than my accord so as you can imagine its pretty frustrating to be fighting this for this long. Any help would be appreciated.
Thanks
Nick

 

clogged lines maybe? or bad rear seals. does your fluid level ever change?

 

Fluid level is always full. Never had to add any. I had a buddy push down on the pedal when the drums were off and both halves of the wheel cylinder moved fine. Any other ideas???

Nick

 

How are the drums and shoes? It seems to me that perhaps the problem might lie in the hardware in the brake drums. If the wheel cylinder seems to work and push the brake shoes with the drum off but will not work when the drum is on, then perhaps there is a restriction on the brakes with the drum on it or something (whether it be springs or the backing plate)

How is the wheel cylinders? I know you said that they push the brakes out when the drum is off but that does not mean that they are not bad, there is less pressure on the cylinders when the drum is off.

Also don’t rule out the Master Cylinder because the prop valve seems to be in order. I had one come in the shop back when I was a tech that had no brakes on the right rear wheel and even though the prop valve checked out correctly and the corresponding front one worked perfectly. In the end it turned out the master cylinder was the culprit and after replacing it, the brakes worked as should.

So don’t rule out the MC

Good luck

L

 

The first thing I tried was to resurface the drums, sand the glaze off of the shoes and adjust them. Still nothing out of the rears. Last week I put new shoes on the rear hoping for anything. No such luck. We just got a whole bunch of freezing rain last night and the streets are all covered right now. Both fronts work equally and lock up with ease. No pulling either direction. The rears however, as always, are just along for the ride. I hear what your saying about the MC but with it being a diagonal split system and the fronts working fine im going to rule it out. I have never seen the inside of a honda prop valve so I have no idea if there was anything in there that could cause this or not. If I get time this week I am going to start cracking lines at the wheel cylinders and work my way forward with someone pushing on the pedal. Hopefuly I will find something. This is getting really old.

Nick

 

Does it lock up with the parking brake?

 

Yea, the parking brake works good. Here lately on snow and ice I have been using the e-brake with the foot brake so at least all 4 tires are braking.

Nick

 

Master cylinder

 

well i am no expert but i know that there really isn't too much to a non abs brake system in general, but if you have checked the lines and pads and stuff and there is no leaks than yeah it sounds like your MS