Brakes Locking Up

[MOverton]

All,



I tried a search but could not find anything. If this has been discussed before please point me in the right direction.



Anyway, About a year ago I changed out the wheel cylinders to one ton cylinders, installed all new hardware, 3" brake shoes, bypassed the RAWL (sp?), and uplugged the box behind the glove compartment. Now the rear wheels grab horribly . It does it quite bit espically if the road is wet and/or the truck is empty. Do I need to install a propotioning valve, new master cylinder, adjust the brakes, or what?



Any guidance would be appreciated. Thank you for you time.

 

[PToombs]

Check your adjustment. When mine get too loose they grab, especially when it's wet. At least til I use them some and dry them out. Might also try to look and see if the wheel seal is leaking oil in there.

 

[dpuckett]

If you put all those upgrades on at once, you may have too much rear brake bias, and may need to back them off a hair. How far down the pedal travel do they come on? If fairly close to the top, I'd say back them off. With my 13x3. 5s, they grab first thing in the morning, but either I get used to it, or they readjust. No more grabbing the rest of the day.



And since Pete and I disagree on theory (but his supercedes mine if his is personal experience, as mine is only theory), only thing you can do is try each one and report back to us how much the new windshield will cost after throwing yourself through it.



Daniel

 

[jelag]

The first place I would look... is to see if the rear shoes are oil coated... . oil, grease etc on brake shoes make them grab.....



Because of weight transfer, the rear brakes on a pickup usually do only 25 - 30% of the braking... if you've got more brake shoe than required... the wrong friction material it would be easy to lock the rear brakes... .



Since you've changed the ratio by installing different wheel cylinders... . I think I'd start by reducing the diameter of the rear wheel cylinders..... by 1/8" - 1/4"... . I'm sure this is going to be a "trial by error" issue

 

[DVolk]

Brakes Locking Up

check your powersteering fluid , if its low it will afect your brakes , includeing air in the system

 

[TWorline]

check your powersteering fluid , if its low it will afect your brakes , includeing air in the system

Never thought about checking THAT! :-laf



I enherited a problem from the PO on my '92, my front brakes never "seemed" to be that good and after replacing the master cylinder & brake booster I found that when he had replaced them he had adjusted the plunger out to far. The large resivoir that controls the front brakes was not getting a full stroke when depressing the pedal, now I have excellent brakes after adjusting the plunger rod on the new booster. Oh yeah, I have the 1 ton brake setup on the rear with a slash & burn on the ABS.

 

[PToombs]

check your powersteering fluid , if its low it will afect your brakes , includeing air in the system

I don't see how this affects anything, as the systems aren't related. These trucks have vacuum assist, not hydraulic assist.

 

[dpuckett]

Ditto on what he said. Power steering is only power steering in 1st Gens. Not that a few havent been converted.....



DP

 

[DVolk]

Brakes Locking Up

Dont think the powersteering pump affects stoping !!!!!!!!?????????



Try empting your resevor and try slaming on the brakes , you will find out



you dont stop any time soon , This is why your powersteering lines run from your power steering pump to your brake booster .



Simply put , no juice in the resevor for steering no stopy .



just dont try this around me as you find out real fast , dont beleive me read the book .

 

[MOverton]

I made a mistake

Guys,



I hate to admit this but here it goes. I had looked at the real wheels several times and never saw anything wet. So yesterday I jacked the rear of the truck up to readjust the brakes and the hub was wet with something. So I pulled the axle and found a leaking wheel cylinder. I woundn't have thought the cylinder would have went bad, they have only been on there a year.



So I guess the moral of the story is take a good look at the situation before you post a question. However I do apppreciate all the post.



I do have one more question, should I replace the brake shoes or just clean them and put the back on? They didn't look fluid soaked but I am sure they have some fluid soaked in.



Again, thank you.

 

[dpuckett]

No more than shoes cost (I think my last 12x3s were in the $25-30 range), I'd put new ones in for peace of mind and safety.



DP

 

[Philip]

DVolk post a pic of your booster setup.



The hydro boost sytem was not used on the 1st gen trucks. It came out on the 94's. If your truck has it then someone converted it over. Which is a good deal for you. It gives you more options as far as braking parts go.

 

[TWorline]

Guys,



I do have one more question, should I replace the brake shoes or just clean them and put the back on? They didn't look fluid soaked but I am sure they have some fluid soaked in.



QUOTE]





You can never really get them dried out enough to have consistent braking, it is always better to replace them.

 

[JLEONARD]

I'd hit them with some brake cleaner and then decide.

I'd probably re-use them after I cleaned them up.

 

[cojhl2]

My experience has been when the brakes get hot the darn stuff boils back to the surface.



With the issue of having to pull the hub, hence a chance for wheels seal replacement on top of everything else not to mention axle nut lock there is no doubt,,, replace the shoes,, both sides!!!

 

[DVolk]

Brakes Locking Up

My 92 has the vacume boost as well .



The system is hydraulic over vaccumme



its bone stock , dont lt that booster fool you follow your hydline they go to the booster , mine truck is 100% stock in the brakeing area

 

[TWorline]

DVolk

DVolk:



OK now I am curious. Here is what all stock 1st. Gens have for a vacuum assisted brake system:



1. A vacuum booster attached to the firewall with one vacuum port/check valve fitting.



2. A vacuum pump which is mounted below the injector pump on the left side of the motor, it sits between the timing case on the motor and the power steering pump ( the power steering pump has two lines connected to it which go directly to the power steering gear box). There is one vacuum hose attached to the vacuum pump and runs directly to the vacuum booster at the vacuum port/check valve connector. From this port vacuum is distributed to the cruise control, to the heater/AC controller and to a vacuum switch mounted to the left fender below the hood hinge.



3. One hydraulic master cylinder attached to the vacuum brake booster with two small steel brake lines connecting it to the brake proportioner.



How does your system vary from the one that I have just described?

 

[dpuckett]

DVolk- double check where that big hose is coming from. If it is like mine and every other one I have seen, it is a vacuum line from the vacuum pump. The Power steering pump is the black little pump on the end of the assembly. The silver (aluminum) thing is the vacuum pump.



DP

 

[cerberusiam]

My 92 has the vacume boost as well .



The system is hydraulic over vaccumme



its bone stock , dont lt that booster fool you follow your hydline they go to the booster , mine truck is 100% stock in the brakeing area

Unless the truck was retrofitted with a gen2 braking setup you do not have hydro boost brakes. Stock was vacuum only. Hydro boost eliminated the brake booster so if you have the big can on the firewall it is vacuum assist braking.

 

[DVolk]

Brakes Locking Up

Ok i guess im wrong my pupmp on my 92 has 2 lines .



but tell me this one , other than some "Gobblin "living in my trucks hood area



My truck had some brake issues and i added powersteering fluid and it went away , the brake resevor was full , i do loose some fluid during the summer months , the brake lid gasket gets weired out ,



But i dont have a littel canister like on my 90 motor in my Suburban im

converting .



This what i think is happening and its still a powersteering lowfluid issue ,



Is that the vaccume pump needs the fluid in the system , since i dont think its a sealed unit , it happend the one time i was low on fluid



check it out for fluid or air in the system



only other possibility is the plunger sticking on the antilock crap



Donovan , my parial mistake sorry