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Brakes have been replaced and bleed and zero change

R

RollTider

NAXJA Forum User
Location
Tusacaloosa, Alabama ROLL TIDE ROLL
I have a 89 XJ non abs, rear 8.25 stock drums, WJ booster and master.
All soft lines, master, calipers, and everything on the rear drums. The calipers are installed with the bleeder up, the drums have been adjusted out, and the master was bench bleed.
Rock hard peddle with the engine off but when I crank it the peddle drops. The brakes wont pump up and are basically ineffective till near the floor. It's been like this every step of the way. No amount of bleeding with different techniques and even got a vacuum bleeder. Assuming no air in the system would possibly be the problem? I've ran out of parts to replace
 
With the age of your rig I would consider a plug in your hard lines. Other than that I had a similar problem with my '66 Cherokee, it was the adj between my booster and the master cylinder!
 
You said vacuum bleeder. You used that at the calipers and brake cylinders, correct?

You say the brakes are rock hard with the engine off. Try putting some vice grips on the vacuum line to the vacuum booster and see if you have brakes, just hard to press when running.
 
old_man said:
You said vacuum bleeder. You used that at the calipers and brake cylinders, correct?

You say the brakes are rock hard with the engine off. Try putting some vice grips on the vacuum line to the vacuum booster and see if you have brakes, just hard to press when running.
Click to expand...


How would that be any different than pressing the peddle with the engine off except for supplying vacuum to the booster that makes the peddle soft only with the engine on???
 
Ecomike said:
How would that be any different than pressing the peddle with the engine off except for supplying vacuum to the booster that makes the peddle soft only with the engine on???
Click to expand...

The booster supplies vacuum assist. Definitely changes the dynamic of the system. If the booster is leaking you will definitely have problems.
 
md21722 said:
The booster supplies vacuum assist. Definitely changes the dynamic of the system. If the booster is leaking you will definitely have problems.
Click to expand...

Yes, but a leaking vacuum booster or bad one way check valve on the vacuum hose will cause the brake peddle to be super hard, not soft, and of course hard to brake. Didn't he say the peddle was too soft (like mine, that I and every one here has failed to find a solution for in 3 years) ??

Mine is super hard with no vacuum and like walking on water with the vacuum applied (exactly like his I think????, Unless I miss read it). The brakes work OK with the engine on, but the peddle is mush 3/4 of the way to the floor. On mine we ran out of parts to replace, some 5 times like the MC. I gave up and just went to driving it as is.
 
RollTider said:
I have a 89 XJ non abs, rear 8.25 stock drums, WJ booster and master.
All soft lines, master, calipers, and everything on the rear drums. The calipers are installed with the bleeder up, the drums have been adjusted out, and the master was bench bleed.
Rock hard peddle with the engine off but when I crank it the peddle drops. The brakes wont pump up and are basically ineffective till near the floor. It's been like this every step of the way. No amount of bleeding with different techniques and even got a vacuum bleeder. Assuming no air in the system would possibly be the problem? I've ran out of parts to replace
Click to expand...

I have had the same problem for 3 years with my 87 Waggy. Ran out of parts to replace and bleed and say prayers over:rolleyes:. Check my last thread this year on it. It has one of the best list of things to try on Naxja, just to see if you missed something.

http://www.naxja.org/forum/showthread.php?t=1124404&page=2
 
Ecomike said:
How would that be any different than pressing the peddle with the engine off except for supplying vacuum to the booster that makes the peddle soft only with the engine on???
Click to expand...

The reason for this test is to confirm that the brake system itself is good. If you have brakes with the vacuum removed, then it isn't a bleeding problem or a bad MC. That would mean the only thing left is the vacuum boost.
 
ASSUMING no air in the system... I've tried using vacuum bleeders in the past and IMO, they suck (and not in a good/normal vacuum sort of way.) My favorite one to use is a little NAPA one with a magnet so you can attach it over the brakes and bleed the brakes yourself. Just make sure you REALLY step on the brake pedal between bleeding wheels lol. Some pedal drop is normal with the engine running because of the brake booster sucking the brake pedal towards the floor. Fords are notorious for "brake booster step-through." But if the brakes aren't kicking in until damn well near the floor, you've got another issue going on. Fluid level dropping at all, even a little? How are you bleeding the brakes? Rears, then front, or just all nilly-willy?
 
RollTider said:
Any idea how to adjust the WJ booster to master??
Click to expand...

You have to separate the master from the booster and adjust the pushrod. Be VERY careful if you feel you really have to do this. If they are a matched set, you shouldn't need to change anything. A quarter turn could effectively lead to the brakes always engaging, burn them and then you have no brakes at all if you need to panic stop.
 
old_man said:
The reason for this test is to confirm that the brake system itself is good. If you have brakes with the vacuum removed, then it isn't a bleeding problem or a bad MC. That would mean the only thing left is the vacuum boost.
Click to expand...

Well I have had that problem for 4 years now, confirmed by 4 new MCs from different sources and 55 gallons :rolleyes: of brake fluid and months of bleeding LOL. But if the brakes work with and with out vacuum and with out vacuum you have a hard peddle and need to press very hard to get good brake action, and the peddle is mush with vacuum, but the brakes still work, how can it be the Vac booster? What can be wrong with the Vac booster to cause that?
 
Ecomike said:
Well I have had that problem for 4 years now, confirmed by 4 new MCs from different sources and 55 gallons :rolleyes: of brake fluid and months of bleeding LOL. But if the brakes work with and with out vacuum and with out vacuum you have a hard peddle and need to press very hard to get good brake action, and the peddle is mush with vacuum, but the brakes still work, how can it be the Vac booster? What can be wrong with the Vac booster to cause that?
Click to expand...

Pinhole in the bladder
 
dan1977p said:
Pinhole in the bladder
Click to expand...

But a pin hole would make a sucking sound, had those many times. Unless there is another kind of quiet pin hole????

And once the pedal bottoms you still have a hard non-booster assisted brake pedal as I recall. Mine acts like an air bubble in the lines that only shows with the engine-vacuum on. But there is no air in the brake lines or fluid leaks. I could stand an elephant on the pedal with the engine off.
 
It was just a guess. I was chasing the same issue and finally gave up chalking it up to 25yo brake system that was still adequate, even if it's not up to the standards of modern vehicles. I won't definitively write it off that way until I've plugged every single line until the pedal remains firm with the car on. FWIW, I had the hard line on the rear axle burst one day telling me I really shouldn't trust any of the hard lines. They could all be soft enough at this point to expand enough to sink the pedal.
 
dan1977p said:
It was just a guess. I was chasing the same issue and finally gave up chalking it up to 25yo brake system that was still adequate, even if it's not up to the standards of modern vehicles. I won't definitively write it off that way until I've plugged every single line until the pedal remains firm with the car on. FWIW, I had the hard line on the rear axle burst one day telling me I really shouldn't trust any of the hard lines. They could all be soft enough at this point to expand enough to sink the pedal.
Click to expand...

While ALL my parts are new, I am still wondering if I don't have a bad new part or two on mine. Like a rotor that is not flat or an odd caliper malfunction.

But I have had this problem for 3-4 years on the Waggy and replaced parts almost one at time (sometimes 2-3 parts) with no changes, re-bleeding has become a career, LOL, after each time. I love mysteries when I tackle them but I hate 4 year old unsolved ones, and am no quitter, HastaLOL.
 
RollTider said:
I have a 89 XJ non abs, rear 8.25 stock drums, WJ booster and master.
All soft lines, master, calipers, and everything on the rear drums. The calipers are installed with the bleeder up, the drums have been adjusted out, and the master was bench bleed.
Rock hard peddle with the engine off but when I crank it the peddle drops. The brakes wont pump up and are basically ineffective till near the floor. It's been like this every step of the way. No amount of bleeding with different techniques and even got a vacuum bleeder. Assuming no air in the system would possibly be the problem? I've ran out of parts to replace
Click to expand...

Did you get the WJ booster and master as 1 unit out of a junk yard or did you buy them separately from a parts place? And if they were bought from a parts place, are they new or rebuilt?

RollTider said:
Rock hard peddle with the engine off but when I crank it the peddle drops.
Click to expand...

When you say "when I crank it" do you mean that you start up the engine and let it run? I'm pretty sure you do but I want the facts.

And when you say "when I crank it the peddle drops", do you mean that when you start the engine, that the pedal actually drops without you touching it?
 
Have you tried jacking up the end of the vehicle that you are bleeding so the air will rise to that section? It might sound like a no brainer but one time I did a brake job on the rear of my bosses dump truck and it took me a while to figure out why I wasn't getting any more air out but still felt like air was in the lines. Finally I realized the rear of the truck was sitting lower than the front. Turned it around and got the rest of the air out. Just a thought.
 
Don't forget to bleed the proportion valve. Seems like I have to coax the shuttle valve below the switch, back to the neutral position after a pressure loss on occasion.

My brake light will stay on if I don't work that sucker back into position:wow:

And back to basics: if the brake pedal doesn't goes down with motor off and steady foot pressure continuously. Then it seems the MC is not leaking nor is there a fluid leak in the lines.

With foot still on the pedal start the vehicle and your foot should drop slightly then be pushed up slightly to a firm pedal.
 
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