breaks problems
11-04-2008, 05:23 PM
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breaks problems
hey people...i just bought my 86 pickup 4x4 oct. 26. and the only thing that was wrong with it was the master cylinder was leaking from the base of the resavor and bubbled were the master cylinder connects to the booster.. to stop the truck i had to pump it to the floor once then pump it to stop the 2nd time.. so i replaced the cylinder brand new not a reman, and i bled the cylinder before i put in on the truck. then i bled the brakes manually and the fluid squirted out like a water gun.. and all fresh fluid.. so now it stopped much better. but every now and then the pedal will be floored and nothing then ill pump it again and perfect.. what could be causing this and how do i fix this problem.. i like to learn when something gose wrong but ill put it in the shop for my last resource. help plz. and thanks much..
11-05-2008, 02:12 PM
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11-05-2008, 02:23 PM
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You have to "start over" on your diagnosis. Assume nothing. The new master could be faulty (rare, but I've seen it). Start with the obvious;
It sounds like you have a primary chamber leaking into the secondary. Does the pedal travel all the way to the floor? On a dual system like the Toy's have, that's almost impossible unless there's (1) a failure on both front and rear hydraulic systems, or you have a leak at the master cylinder. This could be a leak internally too... where the primary chamber leaks into the secondary. Or, it may be leaking directly into the booster.
- Proper bleeding technique as described above (including the load valve)
- Inspect for leaks
- Inspect fluid level (if low, it's leaking somewhere)
It sounds like you have a primary chamber leaking into the secondary. Does the pedal travel all the way to the floor? On a dual system like the Toy's have, that's almost impossible unless there's (1) a failure on both front and rear hydraulic systems, or you have a leak at the master cylinder. This could be a leak internally too... where the primary chamber leaks into the secondary. Or, it may be leaking directly into the booster.
11-06-2008, 10:05 AM
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yea it dose go to the floor but not all the time.. and i didnt know about the load valve. ill start over.. if this still happens and theres no leaks ill get the master cylinder exchanged. and also would the booster have anything to do with this any? cuz i started to buy one of those..the old cylinder did the same thing but it leaked at the base of the resavor.
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11-07-2008, 09:55 AM
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ok i re bled the breaks and the load valve.. nothing.. i still have to pump the brakes to stop.. its doing the samething like before i even replaced the master cylinder...i have no leaks and i made sure all the brake lines were tight.. so im thinking brake booster?? can someone tell me what the symptoms are on a bad booster??
11-07-2008, 10:34 AM
#10
A booster helps make the pedal easier to push, it boosts the force of your foot on the pedal. You could disconnect the vacuum line between the engine and booster and see if you feel any difference in pedal effort. If so then the booster is likely working. You can also pull a vacuum on the booster and see if it holds that vacuum or if it leaks down.
11-07-2008, 03:27 PM
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did you adjust the rear brakes?
and when you replaced the m/c, did you get a rebuild/reman or a new/new one?
sometimes during the rebuild process they do a slight hone to the m/c bore but it's not big enough to install a new oversized piston so they use a standard size piston and seal and they don't work quite right.
and when you replaced the m/c, did you get a rebuild/reman or a new/new one?
sometimes during the rebuild process they do a slight hone to the m/c bore but it's not big enough to install a new oversized piston so they use a standard size piston and seal and they don't work quite right.
Last edited by abecedarian; 11-07-2008 at 03:29 PM.
11-07-2008, 03:46 PM
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No I bought the new m/c. And no I didn't ajust the rear brakes. Can anyone tell me how? And im still losing bake fluid but none of the lines are leaking. Maybe the wheel cylinder is out??
11-07-2008, 03:58 PM
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so no visible leaks, a new m/c and you're still loosing fluid?
I'd head towards the rear wheel cylinders, but it's possible the new m/c is leaking out the back and it's getting inhaled into the engine through the brake booster... but first things first.
And adjusting the rears can be done with a flat screwdriver- remove the rubber plug on the backing plate and using the screwdriver, turn the little 'star' adjuster so that the rear brake shoes put just a little drag on the drums. After that's taken care of, make sure to use your parking/e-brake: it should adjust the brakes if necessary any time the parking brake is applied. I suppose you could just keep pulling and releasing the parking brake handle, but using the screwdriver is probably faster for the initial adjustment.
I'd head towards the rear wheel cylinders, but it's possible the new m/c is leaking out the back and it's getting inhaled into the engine through the brake booster... but first things first.
And adjusting the rears can be done with a flat screwdriver- remove the rubber plug on the backing plate and using the screwdriver, turn the little 'star' adjuster so that the rear brake shoes put just a little drag on the drums. After that's taken care of, make sure to use your parking/e-brake: it should adjust the brakes if necessary any time the parking brake is applied. I suppose you could just keep pulling and releasing the parking brake handle, but using the screwdriver is probably faster for the initial adjustment.
11-07-2008, 05:00 PM
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The thing is, the old m/c acts the same way I have to pump to stop. So I dont think the new cylinder is bad the only problem with the old m/c is that it leaked from the base of the reivore. But I have one shipped this way anyways. And onther problem is I dont think my ebrake works.
11-07-2008, 05:48 PM
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I wouldn't change anything until you know the rear brakes are adjusted properly.
You will have to jack the rear end up so you can spin the tires. Then you turn the adjuster as necessary to cause the shoes to drag on the brake drum when you turn the tire.
and then, re-bleed the entire system.
You will have to jack the rear end up so you can spin the tires. Then you turn the adjuster as necessary to cause the shoes to drag on the brake drum when you turn the tire.
and then, re-bleed the entire system.
11-08-2008, 04:30 PM
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ok last night I took my rear tires off to check the wheel cylinder. The driver side had no pad left on the brakes shoes. The wheel cylinder seems fine. Now on the other side I had some pad left but the rubber ends on the wheel cylinder look like bubbles. So I pushed on on the rubber and black gunky brake fluid oozed out. I had my wife pump the brakes and fresh fluid dripped out of it . The people I got the truck from did not care much a put keeping up with things. So I guess this is my problem? Tell me what you guys think.
11-11-2008, 05:40 PM
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well today i replaced to rear cylinders and new pads and i already put the new master cylinder on and i got like 90% brakes back
when i drive fast and slow down it gos to the floor but other then that everything else is fine. so im thinking brake booster?? i checked the front brakes everything is fine no leaks so any advice??
when i drive fast and slow down it gos to the floor but other then that everything else is fine. so im thinking brake booster?? i checked the front brakes everything is fine no leaks so any advice??
