[Jimongee]

I have a very pristine 2007 Chevy duramax. I purchased it new. Never been in an accident. 170k miles. I’m a former GM tech (retired for years now). So, I still fix all my vehicles problems. However I’m currently having a brake-pull issue that has me stumped. Suddenly a couple months ago I noticed a moderate pull to the right when braking -even light braking causes the steering wheel to lurch right. First of course I checked tire pressures-all ok. Since it was nearing time for new pads/rotors…I did that thinking that would solve the pull-but it didn’t. I made sure all pins were lubed and the pads were not sticking in the caliber brackets. Next I assumed then that the left caliper piston must be sticking and not applying-so I replaced it. This did not help the pull. So next I suspected left flex hose may be collapsed on the inside. So before I replaced the hose I did a few hard brake applies on gravel and confirmed that both front wheels were locking up as they should. So I ruled out a collapsed brake flex hose. I‘m out of ideas. And I need to diagnose and correct the pull. I really appreciate any help on this. I think I have been out of the profession too long…..thanks. Jim in Nashville, TN

 

[davester]

Could the caliper on the other side be retracting more than normal, so the one side grabs before the other?

 

[09W]

'07 Duramax : you have ABS (my '04 2500HD Duramax did).
The 'locked both front wheels on gravel' part is catching my eye. If braking hard on gravel will allow the brakes to lock despite ABS, I don't know that that's a reliable method to check left-to-right balance & disprove a narrowed brake hose. Does "ruled out a collapsed brake hose" mean you didn't replace it?

 

[1999 White C5 Coupe]

I have seen rubber brake hoses “pinched” by the swelling of metal brackets used to hold them in place.

I’d be leaning toward replacing both front brake hoses.

 

[Jimongee]

I have seen rubber brake hoses “pinched” by the swelling of metal brackets used to hold them in place.

I’d be leaning toward replacing both front brake hoses.

Thanks but per my text above; how could the RF & LF brakes lock with even a light apply if either hose was restricted?

 

[Jimongee]

I have seen rubber brake hoses “pinched” by the swelling of metal brackets used to hold them in place.

I’d be leaning toward replacing both front brake hoses.

Re the above response about lock-in on gravel. My bad. I should have stated a that during tho se’ test’ applies each wheel did lock but released and relocked continuous (Hold and release) per normal abs controlled skid. So no I did not replace either brake hose based on that test. And the other comment above the caliper I thought was maybe not applying L side was replaced. I’m still stumped???

 

[ZZ71]

I had the same problem years ago with a K2500 Suburban, a DOT fleet leased vehicle we use on our GPS Survey Team. Truck was pulling to right when braking so dealer rotated tires, stopped pulling. So they started checking tires and found a bad tire. All the oem tires were load range E but one tire that was on the front was a Long Range C. The GY dealer put the wrong tire on when a new tire was needed miles before So replaced all 4 tries per our safety engineers recommendations and no more pulling. Out DOT vehicles had to be safety Inspected any time they were in for service.

Check the tires!!

 

[Jimongee]

I had the same problem years ago with a K2500 Suburban, a DOT fleet leased vehicle we use on our GPS Survey Team. Truck was pulling to right when braking so dealer rotated tires, stopped pulling. So they started checking tires and found a bad tire. All the oem tires were load range E but one tire that was on the front was a Long Range C. The GY dealer put the wrong tire on when a new tire was needed miles before So replaced all 4 tries per our safety engineers recommendations and no more pulling. Out DOT vehicles had to be safety Inspected any time they were in for service.

Check the tires!!

Thanks Mike, I pull a trailer at times so I maintain good matched load rating rubber on at all times with prop inflation. However per your comments I will rotate and see if the prob changes..jim

 

[09W]

I'm still leaning toward the gravel test not really telling you much. I think a wet road braking test would be better.

That aside; if you rule out the calipers, rotors, pads & tires, I would next replace both front brake hoses (& the rear one too).

 

[Jimongee]

I'm still leaning toward the gravel test not really telling you much. I think a wet road braking test would be better.

That aside; if you rule out the calipers, rotors, pads & tires, I would next replace both front brake hoses (& the rear one too).

Ok so first thanks to all who responded. I have finally solved the problem. I noticed that it would only pull to the right at light brake apply, but then as you applied more pressure the truck would stop pulling and brake normally. Since I had already replaced the LF caliper I figured the only thing left was the LF brake hose. When I replaced that part the right pulling was corrected. So the end cause was a partially restricted or partially collapsed LF brake hose. Hope all this helps someone else

 

[davester]

thanks for coming back and posting what the fix turned out to be.

 

[Greg Burr]

thanks for coming back and posting what the fix turned out to be.

beats not being to track a vehicle purchase order