Hard braking = truck pulls to left

Hello again!

Just did all new front brakes on my 94 EX w/ ABS. Replaced both calipers, rotors, slides, bearings and pads. Previous brakes had a stuck caliper on passengers side, so I assumed that was the cause of the truck pulling left. It's better after the new brakes, but only under normal braking.

If I hit them hard, the weight shifts forward instantly and the thing pulls hard to the left. Lately its started locking both fronts as well, like the rears arent doing anything and the ABS isn't working. Rears look good to me. Drums and shoes are pretty new.

Where do you think the best place is to start investigating?

I've bled the heck out of the system with over a quart of fluid and a vacuum pump. Everything seems ok from that angle, but I have no idea where to look. I heard tell of a proportioning valve?

Thanks to all.

M

Rubber brake hoses and hard lines OK?

Appears fine. No leaks, no kinks. I bought new lines for the front expecting a disaster but they were fine so I never installed them.

Did you check all the ABS relays and fuses in the power distribution box?
Are you sure the calipers are on the correct sides?
Is it possible you allowed enough brake fluid to drain out during the caliper swap that you got air into the ABS compressor?

BKennedy said:

Are you sure the calipers are on the correct sides??

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Good point, amazing how often caliper sides are switched. You will never get all the air out unless the bleeders are on top.

Only suggestion I have is to prevent air from getting in when you disconnect the lines; get a toolbox or something heavy and apply the brake just past when the lights come on. This will prevent fluid from coming out.

I'd say bleed it some more but maybe without the vacuum pump. I did mine not long ago and noticed that vigorous pumping of the brake pedal resulted in getting extra air out that didn't come out with light but constant pressure. I had a line disconnected but the line didn't drain, it was the caliper being empty that caused me to have air that only came out with vigorous pumping.

If its pulling to the left then the right side is not working as strong. You could have a clogged hose on the right side or a leak.

vq5speed said:

If its pulling to the left then the right side is not working as strong. You could have a clogged hose on the right side or a leak.

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I second this thought.

You say you HAVE the brake hoses but never installed them? I would start with this because you have them.

I bought brakes for mine yesterday and I was ready to buy a caliper for the passenger side because I have more wear on one side versus the other, and my buddy at the parts store said "I would start with the brake hoses because they may look fine on the outside but the rubber may have failed on the inside where you can't see it."

I haven't installed the brakes yet because I have to buy some of the proper tools to do the job.

Thanks everyone.

I'm going to change out the hoses this weekend and we'll see how we do. Bought a test light and will pull codes from the ABS as well, although the light seems to work and it's always out. Will check relays and fuses to boot.

EDIT:

I'm sure I didn't introduce air into the ABS. Kept a close eye on the reservoir and kept it full during the entire process. Calipers are definitely on the correct sides and were tested to make sure they worked before I drove.

Tire pressure way off?
I had the same problem after a SAS. Gravity bled the brakes for 30 min each line and it helped a lot.
Pull the relays for the ABS and test drive. Rule that out.

Sent from my XT907 using Forum Runner

Well hopefully you get yours figured out this weekend. I hadn't planned on doing my brakes this weekend, but I get to anyway, because my passenger side caliper failed me today as in the piston seal failed spraying brake fluid all over the inside of the wheel. I have the brake hose clamped temporarily.

I wasn't trying to hijack this thread, I was just commenting in the similar thread versus starting another just like it.

BKennedy said:

Pull the relays for the ABS and test drive. Rule that out.

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If I pull both relays and the problem persists, I assume it is NOT the ABS at that point, but if the problem goes away, the ABS is to blame.

Also, when I hit the brakes hard, the pedal doesnt pulse and there is no feeling like the ABS is working. Instead, the fronts just lock up.

mr cribb, check these out. Reasonably priced, powder coated, and usually local availability with a lifetime warranty.

http://www.napaonline.com/Catalog/C...e-Semi-Loaded-Remfd/_/R-SEBSE4747S_0266357873

swshawaii said:

mr cribb, check these out. Reasonably priced, powder coated, and usually local availability with a lifetime warranty.

http://www.napaonline.com/Catalog/C...e-Semi-Loaded-Remfd/_/R-SEBSE4747S_0266357873

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Yeah I had to get the caliper from Napa because O'Reilly was sold out. (Those are my only options in my town)

I didn't get the exact one you pictured but almost identical.

Update

OK, so I replaced the front hoses...amazingly the hard lines were intact so I didn't need to run new ones.

I bled the entire system with a quart of fluid and took it for a test run.

For some reason I now have ABS in the front, which I didnt before. Wheels lock up sporadically but the damn thing pulses which is new!

It still pulls SLIGHTLY to the left, but much better than before the hose replacement so thank you all for the help!

Mkultramega said:

For some reason I now have ABS in the front, which I didnt before. Wheels lock up sporadically but the damn thing pulses which is new!

It still pulls SLIGHTLY to the left, but much better than before the hose replacement so thank you all for the help!

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Great to hear! Rubber brake hoses are hit or miss, can't see flow restriction from the outside. Regarding your ABS lock up,
pulsing, and pull, try CAREFULLY removing the front sensors and wiping them down. If you have the tires off the ground,
spray brake cleaner throgh the sensor holes while slowly turning the tire to clean the tone rings. That helped, but did not
eliminate my slow braking pull. Rebuilt calipers and hoses solved that.

Swshawaii, I pulled and cleaned them a few weeks ago when I replaced the calipers, rotors, bearings and pads. They are pristine, but I feel like the 4WABS has error codes I'm not seeing. My test light should be here shortly and I'll be checking it out to be 100% sure.

Take it for a long drive using lots of brake applications. It might smooth out after all the new parts get worked in together. My hard left pull after the SAS went away after about a 100 mile road trip and the gravity bleeding.