Front brakes locking up and stiff pedal in 5 miles or less a month or two after someone accidentally added power steering fluid instead of.

Tiny
A1AADVANCEDMARINE
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 6.0L
  • 2WD
  • AUTOMATIC
  • 293,000 MILES
Truck listed above is the new body model. So my mechanics helper accidentally put about an ounce of power steering fluid in my brake reservoir. I didn't have any issues right away but maybe a month or two later I started having problems with the front brakes locking up. The pedal starts to get stiff and you can feel the resistance building up until the truck will stop itself once you let off the brakes. Pretty soon the truck will not be drivable or movable. The only way to get it moving again is to crack the bleeder screw on either side of the front calipers. I immediately had my buddy's shop replace the passenger front caliper (old one had a ton of tar and was looking pretty rough) and both front brake lines. I also had him reset the ABS and bled the system. Left his shop and 10 miles or less back to the brakes locking up. He instructed me to remove both ABS fuses and see if that stopped the issue. It has not. I am at a loss and my buddy's shop is too swamped to get me back in anytime soon. I am a marine mechanic and am confident I can sort this out with some help once I get pointed in the right direction. Any insight would be greatly appreciated. (Have Haynes Shop Manual on this truck as well) Thanks 2CarPros in advance!
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Friday, May 15th, 2020 AT 8:49 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

That isn't good. Power steering fluid will cause a lot of damage, quickly. Power steering fluid will cause seals to immediately begin swelling. As the seals swell, they expand and block passages causing issues such as you described. In this case, I feel the return ports in the brake master-cylinder are blocked and preventing the brakes to not release. Also, braking produces heat and the fluid to expand. If the fluid can't return to the reservoir when you release the pedal, due to swollen seals, the brakes remain applied, creating more heat and expansion, and eventually the brakes lock up. Usually, that will happen within a short distance.

The only truly effective way to fix the problem is to take everything apart and replace every rubber part and flushing out the others. Now, since some parts were already replaced, chances are they are now contaminated as well.

I wish I had a better answer, but I feel this is what has happened.

Let me know if you have other questions.

Joe
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Friday, May 15th, 2020 AT 9:32 PM
Tiny
A1AADVANCEDMARINE
  • MEMBER
So the fluid has been filled and bleed a few times before the front brake lines were replaced. I feel confident saying that the power steering fluid would have been flushed out prior to the changing of the brakes lines. I understand that this is a split system and also hydro boost assisted. One other piece of info I forgot to add is that the brakes lock up much faster if the truck sits and idles as opposed to driving. Wouldn't the rear brakes also have been locking up from the power steering fluid put into the master cylinder? I know this is a whole can of worms and if I have to rebuild the entire braking system I guess that's just the route I will have to go. I am doing my due diligence and research and will get this solved one way or another. Just hoping I can purchase rebuild kits for some of these parts and not get sucked into having to buying a ton of high priced parts.
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Friday, May 15th, 2020 AT 10:08 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I have what will sound like a stupid question. Do the brakes lock up when making sharp turns only? There was an issue with the hydro boost systems years ago. The brake pedal would actually move and lock the brakes when making sharp turns.

Honestly, the person that put the power steering fluid in it should have insurance to cover this repair. It wasn't your fault. I'm not sure where you are located, but here in PA, we can't have a business without insurance. I realize he is a friend, but he left you with a mess. I would hope he would make it right for you.

Let me know.
Joe
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Friday, May 15th, 2020 AT 10:28 PM

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