I need help.......please!!!!!! Brake problem.

[dogfriend]

Doh!

I got no clue. Maybe you did get a bad master cylinder. Any chance you can take it back and exchange it?

I'm thinking the Fred Flinstone thing would be kind of cold up where you are.

 

[NH25]

Ok. I am going to ask a really stupid question here. (NO FLAMES PLEASE!)

Have you tried adjusting the rear brakes? If the rear brakes are out of adjustment it will give you a spongy pedal and will feel like there is no pressure in the system. Just my 2 cents worth.

 

[AlaskanJack]

Nope the master cylinder is good I did the test specified in the EB brake article. I isolated just the MC and got great pressure at the pedal.

So if my brakes are functioning (just thinking out loud) i.e. calipers and shoes are moving. Pedal is firm until car is turned on then pedal goes to floor. Only thing added to the system is the power booster. Power booster checks fine per Haynes tests.

What was that wire hanging by the fuse panel? I just happened to notice that a wire was hanging down. It looks like a trailer coupler. I mean its got a male and female connection in a black connector. It some add-on I chased to a splice on the fender well in front of master cylinder. There isn't an electrical connection that would cause these problems is there?

 

[AlaskanJack]

Originally posted by NH25
Ok. I am going to ask a really stupid question here. (NO FLAMES PLEASE!)

Have you tried adjusting the rear brakes? If the rear brakes are out of adjustment it will give you a spongy pedal and will feel like there is no pressure in the system. Just my 2 cents worth.

Well no, the rear brakes are self adjusting.

Ok now I have a dumb question. I noticed that when my rear brakes were activated only one shoe moved. Thoughts?

 

[dogfriend]

I was thinking awhile back that the booster could somehow be causing a problem, but I looked at the tests for it and came to the conclusion that the only thing that might cause a problem is if the pushrod were adjusted wrong; you said that you already checked that.

You could disconnect the vacuum source from the booster to see if that affects it, but I don't know if that would tell anything valueable or not.

 

[NH25]

The rear brakes are self adjusting but more often than not they will not perform this function and will fall out of adjustment. Try adjusting the rear brakes and see if there is any improvement.

If only one set of shoes is moving then you have a bad wheel cylinder. That will also cause the spongy feel and no pressure. Its a simple fix, is really easy to do, and you can get the part at your local parts store.

 

[AlaskanJack]

I moved the vacuum line going to manifold and I could get good suction and someone said that was fine. I am getting a lot of pressure through the outlets at the master cylinder so Im certain the booster is pushing. Could I be getting some blow by. I might need to reverify the measurement on the pushrod, but hate to remove master cylinder again. Maybe this is one of those times where it must go to mechanic.

 

[AlaskanJack]

Originally posted by NH25
The rear brakes are self adjusting but more often than not they will not perform this function and will fall out of adjustment. Try adjusting the rear brakes and see if there is any improvement.

If only one set of shoes is moving then you have a bad wheel cylinder. That will also cause the spongy feel and no pressure. Its a simple fix, is really easy to do, and you can get the part at your local parts store.

What? A wheel cylinder. How can I check for that?

 

[dogfriend]

Ding Ding Ding!

The rear brake slave cylinders are supposed to be double acting (they should push both shoes). Check carefully again, you probably have a bad wheel cylinder like NH25 is saying.

 

[AlaskanJack]

I think the corona's are getting to me!!!

We are talking about the round wheel cylinders that push the shoes right? That would be easy. I will go fiddle with it and see if it stuck.

 

[NH25]

The wheel cylinder is what moves the rear brake shoes out against the drum. I dont know of any way to reliably test them but you would most likely be money ahead to just change them anyway. I have had to put 2 sets of wheel cylinders on my X because of a spongy pedal.

 

[dogfriend]

Originally posted by AlaskanJack
I think the corona's are getting to me!!!

We are talking about the round wheel cylinders that push the shoes right? That would be easy. I will go fiddle with it and see if it stuck.

Just another 5 or 6 Coronas and youll have it fixed!

Yeah, it should push on both shoes.

 

[AlaskanJack]

Yep the driver's side rear is definitely only pushing the front shoe and the rear shoe isn't moving. Called Schuck's and they are 22.95 each. Since I already bought shoes and pads I guess I will go ahead and replace both wheel cylinders.

NH25 where were you when all this started????? I really wish I didn't have to bypass the RABS valve. I just cut the darn thing out and added in rubber tubing with clamps. Now I have to go back in and run new brake lines from master cylinder to rear Y. I just hate having the tubing in the middle a definite failure point.

Any hints for replacing the wheel cylinders? I've never done it, but I like it when I can do it myself. I swore that on this trail rig I would do all the repairs on it.

 

[dogfriend]

You didn't really want that RABS valve anyway

You should be able to add a short piece of hard tubing using two compression union fittings to connect everything. That way you won't have to replace the whole line, just the part that you cut out.

Sorry, I was pretty sure it was the RABS valve.

 

[AlaskanJack]

Dammmmmmmitttttt!!!!!!!


Ok so I have replaced my master cylinder(it is good), bench bled master cylinder, bypassed RABS Valve, replaced rear shoes and both rear wheel cylinders. Bled rear brakes. I can see both shoes on the rear wheels and they aren't moving when I apply the brakes. My RR both shoes move but slightly, LR only my back shoe is moving and again only slightly maybe 1/8".

My last thought is to do the front brakes and then see what is up.

Maybe I'm not getting the rear bled properly. I read about someone power bleeding the brakes. It sounded like a pressure source was attached tothe resevoir and fluid was pressed through the system. Am I wrong about this?

 

[dogfriend]

Bleed the wheel farthest away from the master cylinder first (RH rear) than the LH rear then the RH front and finish with the one closest to the master cylinder.

Yes, they make pressure bleeders, but they aren't absolutely necessary, just more convenient.

They also make check valve bleeder screws, so you can do a one man bleeding job without worrying about sucking air back in. Napa carries them, but they are about $11 a piece which is expensive.

 

[AlaskanJack]

I bought a vacuum bleeder so I could do it myself. But I am having problems getting it to maintain vacuum. I then had my son push the brake pedal for me and I bled them without the vacuum. I put the hose in a cup of brake fluid I had him pump the brakes a few times, then I opened bleeder and he pushed the pedal in and held it. We repeated these steps at least 6-8 times starting with RR then LR. Problem is there was always air in the tube, shouldn't the tube fill with fluid completely? I wasn't getting any bubbles coming from the bleeder.

 

[dogfriend]

Here is how I bled my brakes by myself

I bought these two items:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=46314

and

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=37201

The first item is a big "rabbit" bottle that you fill with brake fluid. It has a 1/4 turn ball valve so you can shut it off, turn the bottle upside down and attach it to the master cylinder reservoir. When you open the valve, brake fluid will come out, but the pressure on the surface of the fluid in the master cylinder will balance with the weight of the fluid in the bottle, so it won't overflow. Therefore the fluid in the master cylinder never runs low while bleeding.

The second item is very useful. It is just a plastic bottle with a magnet built into the lid. You hook the plastic tube to the bleeder screw and then you attach the bottle to the frame (or something else magnetic) above the level of the bleeder screw. When you open the bleeder, the air bubbles will travel up the tube. You can pump the pedal to hurry the process, or if you are patient, you can just let gravity push the fluid out. The main thing is to make sure that the tube is clear of air bubbles, then you know that you got the air out.

 

[AlaskanJack]

Well here is what I was using.

Problem was I pumped it up to about 20lbs of pressure then opened bleeder. I was getting bubbles in canister constantly and the pressure kept dropping in the system, so I close the bleeder and pump it back up and open bleeder. I kept having to do this and I always had air in tube, I expected the tube to finally fill with fluid as all air was evacuated, but it never happened.

I then switched to a tube and bottle with brake fluid in it. I had son pump brakes, then I would open bleeder and he would push and hold the pedal. When I got no more bubbles I closed it and had him pump the brakes again and we went thjrough this process for 8 times. I did the same on other rear wheel with same results.

Now just so I'm not losing my mind, is that not the correct method to bleed the brakes???

Has anyone used the vacuum bleeder that can explain to me how to use it to bleed the brakes?? Same deal I just want to make sure that I am following the correct process and not doing something wrong.

 

[yob_yeknom]

Have your son already be pushing down on the brake pedal before you loosen the bleeder, don't open it then push the pedal.
Make sure he realizes he cannot quit pushing the pedal or let it move up any until after you have closed the bleeder. (didn't state how old he was, not sure if he might be too young to know that)
I've never pumped the brakes while bleeding them, not sure if that would make a difference or not.