Brakes

[toomanytoys]

I dont think the brakes in my 98 work as good as they should.It seems to take a lot of pedal effort to stop at anything over 30mph. I have done pads, rotors, hoses, bled out etc. If I stand on the brake pedal and give it some gas while in drive the truck moves with no problem. The only time I am able to lock the rear wheels is in the rain. I understand this is a heavy truck, but is this normal? If so what can I do to get some better braking performance?

 

[expeditionman]

Could be the brake booster going bad, if these have one. I know my 97 Eb is really soft on the brakes, but I have been told that it is just the way it is cause of the ABS. But it sounds like your losing power. Is the pedal soft/spongy or is it hard to push??

 

[GRIP]

no it"s not the brake boaster all that does is use vacum to make the pedle soft.if the pedle is hard when the motor is running it would be that. but since he saying he doesn"t have enuff presure at the wheels it's most likely the master cylinder the little rubber o ring in there r letting brake fluid by and he is lossing presure.

 

[toomanytoys]

Under normal driving the pedal is soft but it doesnt go to the floor.When I bleed the system out and I get to the front wheels, the pedal gets hard and after I release the pressure the pedal goes down like it should. The next time I do it the pedal goes to the floor and wont pump up. The brake pressure at the rear wheels is really bad. There is very little holding power. I was wondering if this was a normal condition because no matter what I did there was no difference.

 

[GRIP]

like i said it sounds like the master clin. is not holding the presure. there r little o ring in there. it sounds like they r letting fluid by and deceasing the presure to the wheels. but i have 1 ques. do the front wheels lock up when you hit the brakes hard.

 

[GRIP]

he is a diagram of the master 17 and 18 r the o ring thats what is causing your problem.and below you can read up on it.

http://autorepair.about.com/od/otherodddiyjobs/l/aa092504b.htm

 

[toomanytoys]

The front wheels dont lock either. Even in the rain.Short stops from highway speeds is a white knuckle affair.I had to tow a trailer and I couldnt do more than 30mph as I couldnt stop.The mc is the only part in the fluid circuit that I havent changed. Looks like I will have to try it.

 

[toomanytoys]

Well I changed the master and there is no difference. Anyone have a suggestion/idea? Could it be the little proportioning valve on the side of the master?

 

[JUST4FUN]

it is a 98 ill bet that the calipers are frezingup . also with age the brake fluid gets moisture in it causing poor brake performance

 

[toomanytoys]

System has been completely flushed. Calipers and rotors are new.Nothing has made a difference so far.

 

[JUST4FUN]

Check and see how much vacuume you are getting to the booster . look for bad hoses and the quality of vacuumetoo.