Brake Troubleshooting

[SS317]

I've had a brake issue I can't figure out. I thought I had it at one time but everything I try isn't working. I'm throwing it out here for any ideas that you might have.

The truck pulls to the right when braking, really bad. If you're not careful it will yank the steering wheel out of your hand. I'm scared to have my wife drive the truck because she's not physically strong enough to control it.

I have put new front drums on, the shoes are on correct, newer shoes, I've adjusted them so much that I can jack up and R&R the tires in record time.

Still she pulls to the right. When I'm in my driveway, gravel, the right front locks up and skids. The drum is adjusted loose enough on the right side that it easily slides off when the tire is off, yet it still locks up when I brake.

I have changed the brake cylinder at right wheel and nothing has changed.
I have checked each wheel with the tire off and the shoes go out and retract as they are suppose to.

Tomorrow I'm changing the two front rubber brake lines and I'm going to replace the master cylinder. I'm also going to flush the system out again, just in case.

Is there anything else I should be looking at? This has been killing me trying to figure it out. The system seems so simple.

Drums all the way around.........

[blackedoutharley]

First off.... wheel cylinders should be replaced in pairs... if one wheel cylinder is bad the other one is probably just as old and has been exposed to the same stuff that caused the other one to fail. It could be that the L/f isn't working which puts all the braking action on the R/F.

I have found that the most common cause of brake pulls with drum brakes is one of the following (in no particular order):

Shoes installed incorrectly
Shoes not arched to the drums (nearly impossible to do now thanks to the EPA)
Old brake hoses deteriorating internally and acting as a one way check valve
Worn out or incorrectly installed springs / hardware kit.

The most overlooked thing on drum brakes (in my experience) is:

The backing plates get grooves in them where the shoes contact / ride over time and this causes the shoes to stick or hang up.

When I do drum brakes I make it a habit to replace everything (hoses not as often). The cost of a combi kit is less than $20 per axle. I also grind the contact points on the backing plates getting rid of any grooves that may have developed ensuring that the shoes have nothing to hang up on.

I usually replace the front drum with new and resurface the old ones and install them on the rear (same part #).

First thing I would do is confirm that the shoes are indeed installed correctly, replace the other wheel cylinder (depending on how long ago you replaced the other one), install the new hoses and check the backing plates for grooves (and correct as needed). Completely bleed the brakes, including the rears and see if this doesn't correct your issues.

As far as bleeding goes I have never used the "one person job" type... I am old school in this regards I guess. I have somebody pump the pedal while I bleed. Either way it is imperative to get any and all air our of the lines, regardless of how much fluid you may go through.

['63GENIII]

All very good advice. I have had the brake lines deteriorate and so exactly that. It is also possible that the left cylinder is frozen or has more restricted movement than the right allowing the right to "grab" and not the left. I think Blackedout has nailed it here.

[SS317]

Thanks guys. I'll add another cylinder to the parts list.
I have replaced both front suspension springs and will double check they were installed correctly. I'm also putting two new front shocks on today.
I actually have three people bleeding brakes. Me pumping, my uncle turning the wrench, and my dad to hold his and my uncle's beers while he is turning the wrench.

I've been going back and forth about the brake lines acting like one way check valves. I've never seen it but it guess it makes sense.
Thanks again.

['63GENIII]

Gotta make sure to get allthe bubbles out of the beer!
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[SS317]

Ok, after a few beers and staring at the brake we finally figured it out. The new cylinder that was installed was not as tight as it should have been. The cylinder rotated counter clockwise and the brake pad was pushed out over 1/4 inch. The kept the rod coming out of the cylinder to never go all the way back in and in turn caused the front pad to be pressed forward. Any slight push on the brake pedal pushed the forward pad up first, causing a pull to the right.

My uncle found it, totally give the kudos to him. We also installed new rear shocks, fixed the drivers side door so it doesn't droop down anymore, fixed the heater so now I have heat (luckily it hasn't been too cold here in Western Colorado) and she feels like a new truck.