My brakes pull to the left hard - ideas?

[hotrodf1]

Hey all,

Just joined up and was happy to have found a place such as this for these ol trucks.

I just bought a 66 GMC that has been mostly gone through, but something is wrong with the brakes / suspension.

When I hit the brakes the truck pulls to the left. THe harder you brake the harder it pulls to the left. I found receipts where the brakes had been redone, but the note on the work order said something about pulling to the left under braking as well. Apparently the shop couldn't fix it either.

I replaced the shoes (replacing a perfectly good set) and found the wheel cyls in good shape.

I rebled all the lines, LR, RR, RF, LF, still no change.

If I slam on the brakes I think only the LF wheel locks up. THe brakes don't seem to have much grab - got to have a strong leg to stop.

The only thing I can think of is some trash in the lines or something. The brakes are so simple, what else could it be? Some of the lines have already been replaced, so maybe when they did that some trash or something got in there?

I want to drive this thing, but if I to hit the brakes hard, I don't think I coudl get her stopped in time.

Thanks for any help!

[ChiefRocka]

You could have a plugged or collapsed hose. Did you re-bleed the entire system?

Stock single line system ?

How's the brake adjustment...evenly tight all the way around ??

You said slaves are cool, so no oil soaked shoes ??

Other than brakes, suspension is cool ?

[SeanPaintsFlames]

Yeah, I was going to say collapsed rubber line.

[aerotruk63]

I pressure bled my brakes on my truck and on the firetruck as well. This way your sure all the air is out. Sounds like a line is collapsing but why to three cylinders and not just the back? If the truck is up on blocks and someone is pushing on the brake pedal,do all the wheels brake or just the front left?

[justbad]

turn right while braking

[ksbrktracer]

I say brake hoses.......even if they look good, I had a new cheap offshore made hose one time that had issues with, truck always pulled after new hoses, took a while to figure out but the hose was collapsing, put name brand hoses on ......NO PROBLEMS after that

[hotrodf1]

Originally Posted by ChiefRocka

You could have a plugged or collapsed hose. Did you re-bleed the entire system?

Stock single line system ?

How's the brake adjustment...evenly tight all the way around ??

You said slaves are cool, so no oil soaked shoes ??

Other than brakes, suspension is cool ?

I did rebleed the whole system, yes stock single line setup. I didn't pay a lot of attention to the adjusters, thought I was going to do the braking in reverse to get them adjusted right. I did make sure they were nice and freed up and the threads got a coat of synthetic caliper grease.

I did replace the shoes as well in front, thinking maybe there was a problem with them or something.

I should mention that someone decided the easiest cheapest fastest way to lower this ol boy was to heat the springs and drop it one time. I think that's what was down, judging by the look of the springs. It does sit a little lower on the left side, but not more than 1" or so. I know it needs a good set of springs and some lowering spindles to do it right, that'll be next, unless that turns out to be part of the braking issue.

Other than that I think the suspension is alright.

[hotrodf1]

Originally Posted by aerotruk63

I pressure bled my brakes on my truck and on the firetruck as well. This way your sure all the air is out. Sounds like a line is collapsing but why to three cylinders and not just the back? If the truck is up on blocks and someone is pushing on the brake pedal,do all the wheels brake or just the front left?

While I had the peddle held to the floor with a clamp before I let the pressure out of the right front wheel cylinder I did notice that the drum was in fact locked up as if the brakes were working somewhat anyway.

I know that the rubber lines were replaced at one point, maybe with some cheap stuff, that could be it. I'll try a new hose to see what happens.

I noticed that the fluid didn't seem to come out from right front with the same amount of force as the left front. Wasn't sure if I was imagining things or not. Was working in the dark in the driveway. 48 Ford F-1 and 68 Camaro taking up what itty bitty garage I have.

Thanks for the replies everyone, will keep you posted.

[Corts60]

Originally Posted by justbad

turn right while braking

[Corts60]

Definitely check your adjusters.....There should be just a little drag that you can hear when you spin the wheel by hand while it is on jackstands.

[Alan's Classic]

Check your hard lines for kinks or pinched areas if you hadn't already done so.

[hotrodf1]

Tried to put a new Raybestos hose on the pass side tonight, but a storm rolled in and made me run for cover. Just about had it bled, too. Oh well.

I did a cursory check on the lines, but I guess I should probably do that again just to be sure.

[hotrodf1]

Here's an update.

I replaced the brake hose and that didn't seem to help. So I took all the brake lines out of the truck and all the Tee's, blew through all, check them all, replaced the short lines from the tees to the front wheels cause someone had wrecked them previously.

I had been having some issues pressure bleeding the LF wheel. Always seemed to have some bubbles no matter how much fluid I put through. Bleed it the tradtional way and the bubbles aren't there. Took the MC off and tried to bench bleed it, had not much luck after a couple hours and it appeared to leak (maybe my fault, was probably pushing the piston in too far).

Drove to the parts store and bought another new MC (had been replaced by previous owner). That one bench bled no problem, like I thought it should. Now I'm thinking, cool, must be the MC. Installed back in truck along with cleaned out lines, etc. Bleed the system again, things seem to go smoothly.

I take the truck back out and it still pulls to the left when I brake, pretty much acts the same way it did before, although it does seem to have a little better pedal feel, and it seems like it slows you down quicker than before. BUt the pulling is definetely still there.

I'm running out of ideas. I just have to think its in the suspension somewhere. Maybe some bad bushings in the upper A arm or ?????

Anyone have any thoughts of what to try next?

This past weekend someone suggested that I start swapping brake parts side for side to see what that does. The shoes are brand new, shouldn't be that, since it pulled with the old shoes too. Are there different sized wheel cylinders available? Maybe one is bigger bore than the other resulting in more braking force with the same brake system pressure?

[chevysbest92]

maybe one of your drums is warped or turned too far, did u adjust the pads to make sure each wheel scraped as u turned them by hand?

[chevysbest92]

also, is your truck lowered up front, maybe the PO just heated the springs and ones lower than the other, id also check you shock mounts up front, mine are completely loose and my truck does the same thing, parts are on the way

[chevysbest92]

i was just reading what you wrote about the PO heating the spings, i would imagine thats your culprit, if its not even on both sides, the lower side is gunna take most of that weight thats shifting forward, dont quote me though, just makes sense to me, haha

[hotrodf1]

Originally Posted by chevysbest92

i was just reading what you wrote about the PO heating the spings, i would imagine thats your culprit, if its not even on both sides, the lower side is gunna take most of that weight thats shifting forward, dont quote me though, just makes sense to me, haha

The truck actually does sit lower on the driver side as well even without me in it.

I probably need to get some new springs and some drop spindles to do it right I guess. Just not wanting to spend the $

[hotrodf1]

Originally Posted by chevysbest92

maybe one of your drums is warped or turned too far, did u adjust the pads to make sure each wheel scraped as u turned them by hand?

I should recheck this as well I guess. I thought the both had some drag, but I can't remember.

[chevysbest92]

i would check ur adjusters, thats free, or at least cheap if you brake em. lot cheaper than springs and spindles, let me know what the prolem is. i would do what aerotruk63 said, put it all up on blocks, take all the wheeles off and spin each tire while someone is lightly pressing the brake, make sure they all catch at the same time, make sure theyre adjusted so theyre all scrappin too, hope i can help

[ratskin]

One thing that I haven't seen mentioned is that the shoes may be reversed on that wheel. I believe it's the longer shoe to the rear...if it's backwards it'll bite harder and sooner.

[TwoFiftyShifter]

Good point - There are FRONT and REAR shows for each wheel. This is pretty interesting becuase our mostly oeriginal 57 Chevy 3100 pulls hard to the right when braking. I adjusted the brakes on the left side and its a lot better.

[hotrodf1]

Originally Posted by TwoFiftyShifter

Good point - There are FRONT and REAR shows for each wheel. This is pretty interesting becuase our mostly oeriginal 57 Chevy 3100 pulls hard to the right when braking. I adjusted the brakes on the left side and its a lot better.

That is interesting.

When you say you adjusted them, you just tightened up the adjuster until there was some drag?

I thought these brakes were supposed to be self adjusting as you apply the brake in reverse?

I did notice that there were different shoes. The shop that had done it before me had put the shorter shoe in the front, so that's what I did when I redid them. It did not appear that there was a left or right at all that I could tell.

I think I'll attempt to tighten the adjuster on the right front and see what happens.

[TwoFiftyShifter]

Yeah, with the wheel off the ground the left side wheels were spinning freely. Had to turn the adjuster so there was a little drag, and it helped. You might have a bigger problem than the star adjuster though.

[marc70chevy]

loosen up the front left adjuster

[hotrodf1]

I under up tightening the RF adjuster like 4 or 5 clicks and it seems everything is well.

I still don't understand why the auto adjust function didn't take care of that. Oh well. At least it stops now.

THanks for all the ideas everyone.