Truck Pulls Right under Braking

Hi all,

When I'm driving at highway speed (55-85), and I apply semi-strong to strong braking, the truck immediately pulls slightly right. In order to continue going straight, I have to steer left a little bit.

I recently replaced my two flexible brake hoses up front, and replaced my flexible hose in the back.

I also recently replaced my driver front caliper with a new OEM caliper. I rebuilt my passenger side caliper using OEM parts. I replaced my brake rotors and pads. The drivers side rotor and pads are slightly newer than the passenger side.

I installed the new and rebuilt brake calipers with no brake fluid in them. I put fluid into the system by bleeding the brakes with the assistance of a helper pushing the brake pedal. I didn't bleed the LSPV.

After the job, I checked for leaks and found one where the rear flex line connects to the hard line. I tightened that and more more leaks there.

A week after the job, I noticed the brake fluid was low. I assume this means I had a lot of air in the system after the job since there were no leaks at this point.

Is bench bleeding the caliper necessary to get all the air out? Or can I just bleed the brakes like normal and expect an empty caliper to fully fill with fluid?

Is it possible the new caliper brakes slower or less strongly than the old/rebuilt one?

Do I just need another brake bleed?

How can I diagnose my issue? I assume the right side of my truck brakes first, or the right side brakes stronger to make it turn right.

My alignment is very good FYI. The issue only started after my brake job. The pull to the right was really bad on the first day or so. Now it's just very subtle.

 

Are the pads the same material on L & R sides in the front? You mention one side being newer.

If they're the same, I would try to re-bed the pads and rotors. If you didn't bed them in the first place, I could easily see the side with the "older" setup having more bite and having a pull in that direction.

 

The pads and rotors are the same even though they were bought slightly apart.

I did bed in the brakes and rotors to try to break in the newer side and get off any potential brake job residues.

I guess I'll try to go bed them in again. My neighbors think I'm crazy (they're right)... There aren't many empty places near me.

I've driven maybe 600 miles since I did the brake job. Do you think bed in would still be an issue at this point?

 

I believe in aggressive bedding of new pads and/or rotors. I don't know if that's your problem, but it's an important part of diagnosing brake issues, IMO.

If you're doing the bedding on a neighborhood street, I doubt (hope) you're not driving hard enough to get real heat into the materials.

 

Curious... why did you rebuild one of the calipers and replace the other?

Another observation... you haven't properly bled the system unless you bled the LSPV. You need to bleed it first, then pass rear, drive rear, pass front, drive front.

 

Thanks for the LSPV info. I checked the manual and didn't find where it specifies to bleed all 5 in any specific order.

I rebuilt both calipers and installed the pads wrong on the drivers side. While the wheel was able to go on, there was slight pressure on the rotor. This caused pressure on the caliper pins and cracked the casting on the drivers side caliper. I had to throw away the freshly rebuilt caliper due to that...

 

As a follow up, it seems over time the problem resolved itself without changing any parts. I think the brakes bed in, and maybe some bubbles got out of the lines. I did have to add brake fluid over time

 

Also don’t forget to make sure your rear brakes are 1: don’t have a leaking wheel cyl (left would be most likely to cause a pull to the right) 2: are equally adjusted 3: that there is zero air in any part of the system. 4: long shot but never forget tire diameter. If you have mismatched or belt shifted tires that will cause a pull under braking. Glad the situation has gone away but keep these option in mind for future issues. Also just because it’s a new reman caliper that doesn’t mean it’s good fyi. I have gotten many new parts mechanical an electrical bad in the box.