2001 silverado pulls when braking

chevrolet
silverado2500

#1

Ok guys, I’m about to give up. I have an 01 silverado 2500HD. When I first bout it I noticed a worn right front tire and a sight pull to the right. So here’s everything I did. I noticed the rear roters were rusty so I replaced rears rotars, calipers and pads. I also replaced the little metal brake line on drivers side that goes from rubber line to rear differential. I did all that myself. Truck seemed to stop fine. Keep in mind I still had an alignment issue. The next day I took it to my mechanic to get the ball joints done. He ended up doing ball joints, front calipers, cut front rotars and put new pads on and finished with an alignment. After all that I was driving home and I noticed a slight pull to the right when braking. So I took the truck back to the mechanic. He then replaced both front rubber hoses incase they were internally colapsed. Still pulled. He then told me he thinks it is the abs unit and suggested I replace it with a referbished one. I said ok but I need a few weeks. So a few weeks go by and I’m driving home from work and I hit the brakes and my truck pulls hard to the left almost causing me to go into oncoming traffic. I stopped and looked underneath and couldn’t tell what was wrong so I drove it home. I looked under again and I noticed the right side rotar and caliper was tomato red and smoking and even melted my abs sensor wire. I took it back to my mechanic and he replaced my abs unit and since everything was under warranty he replaced both calipers and pads in the front as well. I get the truck back from him and it’s still pulling to the left when braking. What are we missing? I know my story is long but keep in mind and first it pulled to the right and now it’s pulling to the left


#2

Feel all the wheels after a drive to see if any are warmer than the rest (dragging).


#3

I think that’s been determined from the OP’s statement.

Tester


#4

Drive the truck for a little bit and get out and check the temperature of the wheels (carefully!). If one is hotter than the others, that is the one to check. The right caliper was dragging a bit so the truck pulled right. The last time this happened the right rotor was super hot. That means the brake pad faded and the left brake pulled the truck to the left. The problem is with the right side. Concentrate there.

Rebuilt calipers are not always rebuilt well. If, after a short drive, the right wheel is hotter than the left, that caliper is sticking. Could be the caliper itself. it could be the slides. It could also be crud IN the brake lines disturbed when now lines were installed. Bleed the system, check for stickiness in the RF caliper and see if that fixes it before going the ABS unit route.


#5

Front calipers have been replaced twice, system was bleed all the way, and the abs unit has also been replaced but is referbished. Changing the abs unit didnt fix anything. As far as I know those calipers are brand new and not rebuilt unless brand new calipers are just rebuilt calipers.


#6

Then you are left with the rubber brake lines themselves, that feed the calipers.

There can be a bit of broken rubber inside the line that acts like a one-way valve, that lets fluid flow towards the brakes, ie, when you apply the brakes, but that flips down when you release the brakes, preventing the fluid from flowing back to the reservoir, keeping the brake applied.


#8

Rubber lines were also replaced a little less then a month ago. Unless youre saying one was faulty even though it is brand new.


#9

the OP also mentions replacing the brake hoses.

Think!

Tester


#10

Would a faulty abs sensor on the right cause the truck to pull to the left?


#11

Seems a very frustrating and potentially unsafe problem there OP. I understand your concerns. Ask you shop if it is possible to temporarily disable the ABS. Often that can be done by just pulling a fuse. If the problem goes away, meaning this is ABS related, re-bleed the ABS unit. Sometimes that requires special scan-tool equipment that only a dealership or shop who regularly services Chevy’s has.

If it is not the ABS, keep the ABS disabled until you figure out what’s causing the hard pull to the left. That is either caused by one or both of the left wheels braking too hard, or the right wheel not braking hard enough. If I had that problem I’d remove all the wheels (one by one if necessary) and take the calipers off and remove the pads. Then I’d check the rotor for proper thickness and check the rotor run-out on all the wheels. Next I’d remove the pistons for a visual inspection, re-install and make sure the caliper pistons move in and out easily and aren’t cocked in their cylinder, preventing free movement.


#12

Before he put in the new abs until I did try just unplugging it. No change. After he put in the new abs unit I also tried unplugging it. Also no change. Also just an FYI I changed the abs sensors on both sides today and still no change. They didn’t set off the abs light but I figured it couldn’t hurt to try. I also don’t know if this helps but it only pulls when I first initially hit the brakes. Once I straighten then truck out it then brakes straight . It does happen every time I brake though


#13

I’m thinking you might have a loose bushing on a left front A-arm or loose ball joint or tie rod end on that side.


#14

It is possible to get multiple roached replacement calipers, I would lean towards a replacement caliper, then brake booster and master cylinder.


#15

Feeling all four wheels for excess heat after a short (2-3 mile) drive can be helpful to diagnose problems like this. If one is much hotter than the other 3, that hot one is probably where the fault lies. Another thing I’d done for this kind of problem is take the vehicle into an empty parking lot that has a lot of gravel on the surface, or just a gravel-over-hard-dirt parking lot, then do some quick test stops. If one wheel is locking up it is usually evident in the skid marks.

It sounds like the ABS has nothing to do w/it, so that’s one thing eliminated anyway. Good advice from the other posters above, lots of good ideas that need to be tested to confirm/deny.

I’ll add that I had a similar problem w/own Ford truck one time, drums all around, and it turned out to be caused by a leaky wheel cylinder. Brake fluid was leaking out & getting on the inside of the drum, so when I first applied the brakes that side was lubed & slippery and not doing any stopping on that wheel, causing a veer to the other side. But it would straighten out b/c eventually the brake fluid would get wiped away and that wheel would start braking again. So you might have something like that going on. Leaking wheel cylinders (if you got rear drums) or leaking caliper pistons. If you have a leak however, you’d know it b/c the brake fluid would keep getting lower and lower in the plastic bottle. It doesn’t take a big leak to cause this symptom tho, just a little brake fluid on the braking surface will cause it.


#16

You need to determine why the right front brake is dragging, either a mechanical drag at the rotor or the right front is retaining hydraulic pressure. If the right front is retaining hydraulic pressure, loosening the brake line in various locations can show where the problem lies.


#17

The assumption that it’s the brake dragging is logical, however at this stage of the game you may also want to seriously consider the possibility that you have a bad bearing. If it’s 4WD the possibilities grow even. At this point I’d want to pull the whole RF off and take a look-see at the bearings… or even just replace them.

A corner with something dragging, whether it be a brake or bearing, can get very hot. I’d recommend a non-contact infrared thermometer, about $25. It’ll allow you to accurately see heat without the risk of burning yourself. And once you have one, you’ll discover endless uses for it. I even use mine to find my next house project by “mapping” the temperatures around the outside walls/doors/windows in the winter.

An ABS modulator works by interfering with the application of brakes on an individual line. When the wheel speed sensors see that one wheel has stopped rolling, it assumes it’s slipping and sends a square wave to a solenoid in a needle valve in that wheel’s hydraulic line (brake line), causing it to open and close rapidly (pulsate). While it is possible for a valve to stick closed and keep the line pressurized causing continuous braking, it would be highly unusual. Brake line pressure on a big truck can exceed 2000psi, and that’s enough to overcome a sticky modulator valve. Typically they fail by failure of the solenoid-operated valve to close. The brake still works, but loses its ability to pulsate and the CEL trips. The ECU monitors the system’s performance.

While I realize that you’ve already isolated a serious failure of the RF brake as well as abnormal RF tire wear, which suggests that in your case it’s definitely a RF problem, pulling while rolling can also be caused by a rear brake dragging, including a parking brake.

Is this truck 4WD?

Also, are you the original owner? If not, you may even want to have a friend follow you down the road to look for “crabbing”, a condition wherein the body/frame move at an angle as the vehicle goes straight. Such a symptom suggests a prior accident and possible bent frame or improperly installed rear axle (crooked on the frame).

Just some food for thought.


#18

So problem solved. My mechanic just put on my abs unit so I trusted he bleed the brakes properly. I was wrong to trust that. I just bleed the right side myself and now it stops straight. Thanks for everything guys


#19

Outstanding.
Sincere thanks for taking the time to post back and let us know. It really does feel good to know a problem is solved.
Happy motoring.