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Rear drum brakes lock up have replaced the

Rear drum brakes lock up have replaced the proportioning valve, master cylendar and have bleed out all 4

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6ya6ya
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Posted on Jan 02, 2017

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dxg031603
  • 9 Answers

SOURCE: 1986 gmc sierra 1500 front rt brake locks up

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

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motor1258
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SOURCE: hi - emerg brake cable snapped and rear wheels are locked up -

If main cable is snapped, you may get them to move for you by spraying cables where they go into backing plate, and give them a sharp/quick rap with a screwdriver handle or similar. I've got a way with that a few times. rap, rap, rap, rap repeat, and sometimes it will save restling with adjusters. I am curious though, if they weren't partially seized prior, they should have released when cable snapped.Get back to us if that doesn't work.

Posted on Dec 26, 2008

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SOURCE: The master cylinder brake lines broke before the proportion valve

Obviously you have a bunch of badly rusted lines. Better they failed while you were working on them rather than driving down the road! Carefully inspect the remainder of the lines and if in similar condition to the ones that failed, you need to replace them. When finished and system is tight, then bleed out system. (check it twice to ensure all air is gone.)

Posted on Mar 19, 2009

  • 1779 Answers

SOURCE: bleed brakes but no pedal

Good! You bled the master cyl. before installation! The proper order of bleeding the lines, is to start with the wheel the greatest distance from the master cylinder. Then work your way to the next greatest distance, and last, the closest wheel. Make sure all air is removed from the lines before you proceed to the next wheel, and frequently check the master cyl. level, because, as I'm sure you know, if you **** in air at the master, you have to start all over again. I'm assuming you don't have a power bleeder, so with a helper do this with car running (make sure it's on safety stands and not going to fall on you!) Pump pedal 3 times, no need to mash the pedal into the floor, just 3 pumps 1/2 way down, hold 3rd pump at half way down level while bleeder is opened, when flow is about to stop at bleeder, close bleeder and repeat til no evidence of any air. Let me know how it goes and if you need any help.

Posted on Apr 21, 2009

Rayvin1943
  • 97 Answers

SOURCE: No fluid to rear brakes on a 1992 Lincoln

check at the proportioning valve--some have a pin that sticks out from the side, when bleeding the brakes try to push that pin back in. But first check to see why this happened--fluid leak to rear wheels, brake hoses cracked and air getting into the system??????

Posted on Jun 12, 2009

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1 Answer

Fleetwood problem


Pretty normal to not be able to lock the brakes without the assistance of the booster, it'll take a lot of pedal pressure without it. It's also normal for the pedal to feel harder without the booster, this goes for any car/truck with power brakes. Try it with any other car you have and you'll see.

I've worked on several old Cadis but don't recall what year they started using front disc. If it's been changed from drum to disc you'll likely need a different proportioning valve and possibly a different master to get them to work right. Talk to the seller and ask if the brake feel changed when they replaced the master and if they changed any other parts.

Mar 31, 2017 | 1968 Cadillac Brougham

1 Answer

Replaced rusted brake lines but did not replace valve in rear lines will this cause brake fade in 1995 bonneville


BY brake fade away I take it that you mean the pedal goes to the floor after you taken your foot off the brakes. . The valve you left out is a compensator valve that proportions the pressure between front and back to stop rear brake lock up and side skidding. I think the problem is in the master cyl in that the nonreturn valve under the second piston is not working and hold residiual pressure in the rear lines (Assuming they are drum brakes). If not you will need to bleed the m/cyl by cracking the lines at it one ata time and emptying the cylinder of trapped air allowing a full charge of fluid every time you pump the brakes.

Mar 10, 2013 | Cars & Trucks

1 Answer

Calipers keep locking down


are you serious ? this should not happen , it tells me your master cylinder is @ fault , too much pressure, unbalanced system, not enough pressure to rear drums, bleed improperly, if you have abs brakes which I 'm sure you do, maybe the proportioning valve is stuck, should be in a balanced position. if bleeding does not help to resolve this, then replace the valve, rebleed the entire system, according to spec, back to front, LR,RR,RF,LF. UNLESS YOURS IS DIFFERANT. if you also suspect master cylinder, replace it also. but the VALVE needs to be replaced no matter what !

Mar 07, 2013 | 2005 Chevrolet Silverado

1 Answer

I just replaced the brake master cylinder and rear wheel cylinder on my 1987 toyota pickup, and now I have no fluid going to the back brakes. Bleeding them does nothing


check for fluid before and after the proportioning valve by disconnection the line after the valve and applying the brakes, if no fluid after valve try before valve if fluid is there then it is a bad proportioning valve. you did bleed the master cylinder before connecting the brake line and trying to bleed the brakes all at once right? If the master cylinder was not bled first then a lot of air may have been forced into the rest of the brake lines.

Oct 01, 2011 | 1987 Toyota Pickup

2 Answers

1971 chevy 3/4 truck, front disc and back drums, i lost all brakes. Thought it was the master cylinder because the rear master cylinder port emptied itself of all fluid and no leaks on the rear wheel...


to bleed the brakes & should be done w/proportioning valve in place - you start at farthest corner - right rear, left rear, right front and left front.... If you suspect proportioning valve you can pick them up cheap at any salvage yard.

Feb 21, 2011 | Chevrolet 2500 Cars & Trucks

2 Answers

Rear brakes locking(until abs kicks in) with little front brake application and very light pedal pressure. also have really poor hard/emergency braking response, vehicle doesnt stop as aggresively as it...


It could be a proportioning valve, and there's also the chance that the portion of the master cylinder that operates the front brakes is going bad. Have you had a pressure check done on the front brake system? Also, some vehicles have a variable proportioning valve, so that when the vehicle is loaded, it allows more pressure to the rear brakes. These can sometimes stick in place, causing the fault that you describe. Hope this helps you out.

Dec 01, 2009 | 2002 Dodge Durango

1 Answer

I need a diagram of the entire breaking system on a 1993 ford taurus i just replaced a rear line and i think i stripped the extention piece i had to add to the end of the break line. the one that goes into...


here is a 96 taurus

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Item Part Number Description 1 2C296 Anti-Lock Brake Tube 2 2C219 Anti-Lock Brake Module 3 2005 Power Brake Booster 4 2263 Front Brake Tube 5 2B091 Brake Pressure Control Valve 6 2140 Brake Master Cylinder 7 2B547 Brake Load Sensor Proportioning Valve 8 N802191-S60 Bolt 9 2L568 RH Rear Brake Tube 10 2L569 LH Rear Brake Tube 11 2C287 Brake Fluid Distributor Tube 12 N808531-S301 Bolt 13 — Front Side Member 14 N802324-S56 Bolt 15 18124 Front Shock Absorber 16 2B121 Front Disc Brake Caliper 17 2078 Front Brake Hose 18 2264 Front Brake Tube 19 2553 Rear Disc Brake Caliper 20 2A442 Rear Wheel Brake Hose 21 N808728-S60 Bolt 22 — Side Rail 23 N802324-S60 Bolt
Brake Load Sensor Proportioning Valve

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Item Part Number Description 1 2B547 Brake Load Sensor Proportioning Valve 2 — Body 3 N802191-S56 Bolt (2 Req'd) 4 2L568 Brake Tube Assy 5 2L569 Brake Tube Assy 6 2265 Brake Tube Assy 7 2B255 Brake Tube Assy 8 5500 Rear Suspension Arm and Bushing 9 W611634-S301 Bolt A — Tighten to 11.4-15.6 Nm
(8-12 Lb-Ft) B — Tighten to 10-14 Nm (7-10 Lb-Ft)

Brake Hose, Rear —Drum

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Item Part Number Description 1 — Rear Side Rail 2 2L569 Rear Brake Tube 3 N602324-S60 Screw 4 N611193-S60 Screw 5 2C023 Left Hand Rear Hose and Connector 6 2210 Rear Drum Brake Backing Plate 7 18125 Rear Shock Absorber 8 2267 Rear Brake Tube A — Tighten to 16-20 Nm (12-15 Lb-Ft)

May 10, 2009 | 1993 Ford Taurus

1 Answer

I have a gmc 2500 4x4 and rear brakes locking up


Do you have a/the proportioning valve in your system? Pin needs to be pulled out for centering while bleeding.

Jan 25, 2009 | 1985 GMC C2500

1 Answer

I have a Jeep Wrangler 1992. Replaced rear axle with a Ford 8.8 axel rear end and installed all new brake rotors, callipers, hoses, metal lines, forward brake discs, hoses. Have bled reapeatedly....pumping...


The proportioning valve most definately can be the problem. Did you change it or is it the original? (A disc/drum system uses a 70%front/30%rear braking ratio, whereas an all-disc system is alot more even). I would first bleed the master cylinder. Then I would 'gravity bleed' the rest of the system by opening the bleeders on all 4 wheels. Do not at any point let the m/cylinder go dry. Also, do not touch the brake pedal.
Continuously check all 4 bleeders, when clean brake fluid with no bubbles at all is running from a bleeder, close it. When all 4 wheels are done, recheck the fluid level and you should be OK.
Pump the pedal to 'self-adjust' the rear calipers, then re-check the fluid level.
Any problem after that means you either have a loose connection (it's possible for a tiny leak to let air in, but not let fluid leak), a leak, or you need a new (disc/disc type) proportioning valve. I would try Summit Racing myself. Good Luck!

Dec 26, 2008 | 1992 Jeep Wrangler

4 Answers

1999 Cavalier rear brakes engage and lock up before front brakes engage. Any ideas?


you have to change the rear to the front line on your master cause of the proportioning valve is not on the good wheel

Jul 15, 2008 | 1997 Chevrolet Cavalier

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