Question about 1999 GMC Sierra

1 Answer

1986 gmc sierra 1500 front rt brake locks up

I have replaced the caliper and the proportional valve. After applying the brakes several times the rt front locks up. I have bled all 4 and the only way to release the front rt is to open the bleed valve on the caliper. Could it be a brake line or master cylinder? All other brakes seem OK.

Posted by on

  • 4 more comments 
  • Anonymous Jan 12, 2009

    I've got a 1985 GMC 1ton I've replace the Hydro Booster, MC, Front break lines and the Calipers, After hitting the breaks the front wheels lock up. and the peddle want come all the way up HELP ME PLEASE................

  • AmberLeigh4u Mar 18, 2009

    I have a 97 with the same problem.Changed the rotor .pads,caliper and berings..blead the brakes and now the driver front is locked up.When bleeding the air I can see the capiper trying to bounce back but not back enough to keep it from locking..also put my hand on the proportion valve where there is a rubber cap and that seem to be working..what could I replace next? Amber

  • Anonymous Mar 16, 2014

    my cargo van lockout the driver side caliper when brake all the time some vary sed to mi than the hidraulic valve unit is damaged i replaced all ready master cylinder brakes hoses ,calipers, speed, sensors ,bleeded all system and not works what i can do please?

  • Anonymous Mar 30, 2014

    I am wondering if my master causing this problem or do I need look at something between master and brake calipers

  • Anonymous Mar 30, 2014

    Was wondering if my master cylinder is bad or is there something else between the master and the brake calipers needs to be looked at

  • Anonymous Apr 01, 2014

    My 02 GMC Sierra 1500HD brakes will slowly put themselves on and then lock up. I then have to stop and put the brake pedal right to the floor for a minute then it releases and is good. The power steering pump has a little whine to it when the motor is reved up.



1 Answer

  • Level 1:

    An expert who has achieved level 1.


    An expert that hasĀ over 10 points.


    An expert whose answer gotĀ voted for 2 times.

    Problem Solver:

    An expert who has answered 5 questions.

  • Contributor
  • 9 Answers

Check brake lines they may have gotten pinched very commonok new c/k trucks when you crank the torsion bars up to far you may have hit something and pinched the brake line check those before messing with the master cylinder those are a real pain

Posted on Sep 21, 2008


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya Mechanic can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
click here to Talk to a Mechanic (only for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

How do I check and/or find a brake proportional valve oem replacement part for a 1999 Lincoln Continental

proportional valves are designed to give the right amount of hydraulic pressure to the back brake to prevent them locking up with a resultant loss of control of the vehicle
replacement of calipers would only be need once to fix jammed or leaking pistons but the pads may have to be replaced more often.
if it only the front brakes that is the problem ,I suspect that the fault will be in the compensating ports of the master cylinder that is not releasing the fluid back into the reservoir and the resultant heat build up from the pads still in contact with the discs is building up brake pressure and so keeping the pads on the discs to the point where lock up is evident
failed proportioning valves will result in no brake action to the rear wheels or rear wheel lock up
If parts are not available from the manufacturer spares department, they should be still be available from reputable brake shops as car manufacturers do not make brake parts as such but rely on brake manufacturers to supply items to specifications
the unit will be repairable by an accredited shop and failing that would be available from the wreckers.

Aug 07, 2015 | 1999 Lincoln Continental

1 Answer

Brakes wont realese 87 GMC 1 ton how to check brake proportioning valve

A stuck proportioning valve will only prevent either the front or rear or corner / corner from working, it wont make them stick. More likely its one or more frozen brake caliper/s or a bad rubber brake hose/s or frozen brake cables etc.. Is it only front, rear, or both, one left, one right one side or all 4 ? You're gonna have to get the wheels off the ground even if only one at a time to check them. To determine if it is a bad rubber brake hose Crack open a bleeder screw. If the wheel then spins freely replace the hose. If it is still stuck then it is a stuck / frozen caliper, replace the caliper. In the case of rear drum brakes, you can checck the hose in the same way or if it's stuck cables you can try tugging hard on the cables to free them up some but otherwise you'll probably have to pull them apart and do a complete brake job including wheel cylinders.

Mar 09, 2015 | GMC Cars & Trucks

1 Answer

Front brakes

if the proportioning clogs or damaged it can cause brake problems such as yours take pressure readings on all 4 calipers the proportioning valve is just as it says differentiates the pressure front to back also the abs unit itself can cause the same problem also

Jun 25, 2013 | 2000 GMC Envoy

2 Answers

Brakes lock up after about 10 miles

did you check the brake booster ? how long you use the brake booster? may be have no enough pressure in vacuum brake booster. get more details here for help :

May 22, 2013 | 2005 Chevrolet Avalanche

1 Answer

I have a 1997 GMC Sierra 1500, and it had drivers side from pads locking up and heating. I changed the calipers , rotor and bearings. I took it for a test drive and its the same problem. I can feel a...

You need to replace the rubber hose going to the brake caliper from the metal line. The inside of the hose is breaking down inside keeping the caliper from releasing. Hope this helps please leave comment.

Feb 25, 2011 | 1997 GMC Sierra

1 Answer

2006 chevrolet 1500 brakes shimmy without touching them,also when setting still mash couple times let off ,wheels hard to turn

check for front brake calipers dragging, if the are replace calipers and front brake hoses, if calipers ok replace master cylinder, This is how to check calipers, jack up front of truck have some one apply brakes and release as soon as they release the brake peddle the wheels should spin freely if not brake the brake line lose at master cylinder if wheels spin free with line loose replace master cylinder, if not replace calipers and hoses.....HOPE THIS HELPS

Nov 16, 2010 | 2006 GMC Sierra 1500 2WD

4 Answers

I have a 1999 gmc sierra .the front brakes lock . its a 2 wheel drive . what is the problem

Could be the proportioning valve, master cyliner or the front calipers going bad. You didnt say the milage or if you have had the brakes serviced.

Feb 16, 2010 | 1999 GMC Sierra

2 Answers

1989 G20 Van right front brake is locking up when applied. Calipers replaced. Did not fix problem.

The piston is binding in the wheel brake cylinder, perhaps a bit of rust in the cylinder.
Inspect it, replace wheel brake piston and maybe the cylinder if you can't make it "smooth".

Sep 21, 2009 | 2000 GMC New Sierra 1500

1 Answer

1989 K-1500 Brake Problems

Did you replace your front brake lines as these are rubber and after time collapse causing the truck to pull in the opposite direction! In your case I'd say left front is crimped and blocks fluid and makes right front pull to the right. This is a common problem and one of the first items to replace on these trucks and at $30 cheap insurance.(REPLACE BOTH).

Mar 17, 2009 | 1986 Chevrolet K1500

Not finding what you are looking for?
1999 GMC Sierra Logo

661 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts


Level 3 Expert

77544 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22306 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6927 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides