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Having trouble with brakes.

Khary23 said:
I'm gonna order a new booster today. They have an A1cardone remanufactured on amazon. Does anyone have any opinions on that company, and or reman boosters in general?
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I'm no fan of theirs, from getting burned with a series of steering boxes back in the Seventies, to a crappy rebuilt master cylinder two years ago. But they are the biggest, and in many cases the only company available, so they must be doing something right.

In reviewing your post, I'm thinking that it's the MC, and not the booster. The booster doesn't give you a high or low pedal, it just makes pushing it easier. I had good luck with a new MC from NAPA, and it was cheaper than the re-man (that didn't work) from the aforementioned company.
 
heyhar said:
I'm no fan of theirs, from getting burned with a series of steering boxes back in the Seventies, to a crappy rebuilt master cylinder two years ago. But they are the biggest, and in many cases the only company available, so they must be doing something right.
Click to expand...

Oh crud ordered it before reading this

heyhar said:
In reviewing your post, I'm thinking that it's the MC, and not the booster. The booster doesn't give you a high or low pedal, it just makes pushing it easier. I had good luck with a new MC from NAPA, and it was cheaper than the re-man (that didn't work) from the aforementioned company.
Click to expand...

I just replaced the MC last weekend, and absolutely no change in the breaking.
 
Have you tried adjusting your rear drum brakes? The self-adjusters are notorious for not living up to their name. If they are far out of adjustment, the pedal will have a lot of travel before getting firm. When I first looked at mine, the shoes were backed way off the drums, and adjusting them made a huge improvement in brake feel. Now I try to do it every 1000 miles or so.

Otherwise, I think you have a pretty good hydraulic leak somewhere. I don't see what a new booster is going to do for a soft pedal - if anything, a bad booster would make the pedal overly firm.
 
Robs92XJ said:
Have you tried adjusting your rear drum brakes? The self-adjusters are notorious for not living up to their name. If they are far out of adjustment, the pedal will have a lot of travel before getting firm. When I first looked at mine, the shoes were backed way off the drums, and adjusting them made a huge improvement in brake feel. Now I try to do it every 1000 miles or so.

Otherwise, I think you have a pretty good hydraulic leak somewhere. I don't see what a new booster is going to do for a soft pedal - if anything, a bad booster would make the pedal overly firm.
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I will try adjusting the shoes tomorrow, and see if that helps.

I am pretty sure that I do not have a leak because the fluid level has not changed at all.

Is there a sure fire way of testing to see if my new master cylinder is bad?
 
When you install the new booster, be sure to adjust the pushrod properly! There should be a few millimeters of play in the pedal before the booster pushrod makes contact with the master cylinder. The fluid in the brake system expands as the brakes are used, and if there's not that free play in the pedal, your brakes will lock up as you drive. (Don't ask me how I know that).

Also, be sure to adjust the brake light switch after changing the booster out, because the pedal height might have changed enough to trigger the brake lights when you're not pushing the pedal. (And that can kill your battery if you don't realize it for a day or two. Don't ask me how I know that either).
 
It tells me that possibly your rear brakes aren't doing a good job. By design, disc brakes stop a car better than drums, and they cool faster. But, drums hold a stopped vehicle better, which is why even modern cars have a small drum parking brake within their rear discs. At some point, you will have replaced just about every component in your braking system, but when you throw in today's poor quality parts, you may pass by the original problem, and focus on the next thing in the system

By the way, my money is still on the MC!
 
Khary23 said:
The brakes do not hold at all if giving gas.
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Do you mean that if the Jeep is stopped, and you rev the engine, that the pedal feel changes? Because that sounds like a vacuum issue.

Or do you mean that if you try to drive while applying the brakes, the brakes don't prevent the car from moving? Because then I'd agree with heyhar that it sounds like your rear drums need to be looked at.
 
Khary23 said:
Forgot 1999 31" tires 4.5" lift
new calipers, pads, rotors, drums, and shoes last year.
Click to expand...

You don't mention rear cylinders, soft lines, hard lines, brake hardware, etc. Replacing all of these gave incremental gains in various cars through the years, especially in my '96. As these beasts age, they all exhibit various symptoms, so tracking them down becomes more fun.

You mention a stiff pedal when blocking the ports on the MC. Maybe we can assume that it's OK. My next focus would be the lines to the rear. I'll bet the fluid wasn't changed every three years like recommended. This leads to corrosion and clogging, greatly diminishing the flow of fluid, and the force. Most likely you get enough flow to bleed, but possibly not the volume for effective braking action. I've seen enough unbelievable stuff when it comes to rear brakes that nothing surprises me anymore.
 
heyhar said:
You don't mention rear cylinders, soft lines, hard lines, brake hardware, etc. Replacing all of these gave incremental gains in various cars through the years, especially in my '96. As these beasts age, they all exhibit various symptoms, so tracking them down becomes more fun.

You mention a stiff pedal when blocking the ports on the MC. Maybe we can assume that it's OK. My next focus would be the lines to the rear. I'll bet the fluid wasn't changed every three years like recommended. This leads to corrosion and clogging, greatly diminishing the flow of fluid, and the force. Most likely you get enough flow to bleed, but possibly not the volume for effective braking action. I've seen enough unbelievable stuff when it comes to rear brakes that nothing surprises me anymore.
Click to expand...



heyhar,

I replaced the lines with extended stainless steal lines. the hardware for the rear is new, it came as a kit with the drums, and shoes. The wheel cylinders have not been replaced. I think you are right about the fluid. When I replaced the MC the reservoir was really dirty. I should be getting my pressure bleeder from motive today and I will change the fluid, and see if that helps.

Brake line set
http://www.quadratec.com/products/72406_812X_PG.htm

Brake kit
http://www.quadratec.com/products/56216_06.htm
 
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We have the Motive bleeder, and my son swears by it!. Me, I'm old skool. My wife knows the drill, and I can hear her sigh when I tell her it's time (to bleed the brakes, that is!).

My son is going through pretty much the same frustration with his '96 Classic. A few MCs, new lines, hardware, etc., and he's got it down to tweaking the rear brake adjustment. It's hard to get a good feel for proper adjustment with a Posi rear, though. Everything wants to spin when you are trying to check the brake drag on each wheel.
 
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Just finished changing the fluid, and still nothing. I am almost about to give up and take it to a shop. I guess we will see what happens with the new booster when it gets here.

The lines out of the MC does one go to the front and one the rear? The reason I ask is that when I connected a line to the front port the pedal got firm. When I then connected the other line to the rear port the pedal got soft.
 
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The two lines out of the MC should go to the proportioning/distribution block, which had three outputs-one to each front wheel, and one to the rear. A suggestion-when you get your power bleeder, pressurize the MC, then gently crack open the outputs of the dist. block, just till you get some drips. You are looking to bleed out any air trapped in there. Just have a rag you don't like, or a wad of paper towels under the drips. Brake fluid doesn't like paint. Just a quick crack open, under pressure. No squirting for distance!

I realize I'm grasping here, but I've been in your place more than once.....
 
heyhar said:
The two lines out of the MC should go to the proportioning/distribution block, which had three outputs-one to each front wheel, and one to the rear. A suggestion-when you get your power bleeder, pressurize the MC, then gently crack open the outputs of the dist. block, just till you get some drips. You are looking to bleed out any air trapped in there. Just have a rag you don't like, or a wad of paper towels under the drips. Brake fluid doesn't like paint. Just a quick crack open, under pressure. No squirting for distance!

I realize I'm grasping here, but I've been in your place more than once.....
Click to expand...

I will give it a try tomorrow if I get home early enough if not Sunday for sure.
 
Khary23 said:
Just finished changing the fluid, and still nothing. I am almost about to give up and take it to a shop. I guess we will see what happens with the new booster when it gets here.

The lines out of the MC does one go to the front and one the rear? The reason I ask is that when I connected a line to the front port the pedal got firm. When I then connected the other line to the rear port the pedal got soft.
Click to expand...


It is hard to beleive that the XJ breaks could beat so many experts for so long. I always thought that doing breaks was routine and an easy fix.


Having said that,... You said the breaks got bad over a period of time. Assuming no one messed/changed anything on the breaks and the master cyliner did not run out of fluid the only thing to assume is that something deteriorated over time. A spongy break pedal is not an indication of a bad break booster. This is indicated when the engine stalls on a moving vehicle. The break pedal get higher and firmer when the vacumn is depleted.

I would look other areas of the break system. In post #55, you have verified the master cylinder is good and build good pressure all be it when the rest of the breaking system is removed and the ports plugged. Now turn your attention to the propotioning valve. It may be possible some thing in it have gone South.

Next, work your way down to the calipers and wheel cylinders. Check that the hoses do not swell under pressure. If possible, get a break pressure guage and check the pressure at the wheels. This will tell you if there is enough pressure is getting to the wheels.

One other thing,...I know this is a long shot but check that the lines fron the master cylinder ar connected to the correct port on the propotioning valve.
 
I don't know that there's anything to check inside other than the 'piston' slide inside that activates the switch to light the BRAKE lamp to indicate a problem.
 
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