O.T. ANYBODY works on older Jeeps ? need HELP !!!

Dutchman

Well-known Member

I been trying to get a 1996 Jeep Cherokee going .. it sat for a couple years , NEED BRAKE HELP ...

Here's what I have done so far .. Back brake's Good .. Front .. replace the rotors , Calipers , and new brake pads ...
I bleed the brakes 4 times and the last 3 times had a great stream right from the start { all 4 wheels } .... the brake pedal goes to the FLOOR ... pump the brakes and they come up a little and that's running or not running ...
So I was told I had a bad master cyl. .. so I replace it ... SAME THING .. { YES I bleed the brake's 3 times this time } still no pedal ...
I have someone in the jeep pushing the pedal down slow as I bleed them ...
WHAT AM I MISSING >>> I never had anything like this before ....

THANKS for ANY advice you want to share .................... mark
 

SORRY I guess I don't know what that means .... I put the tank on the new one from the old one and put it on the jeep and filled it , and started to do my bleeding thing ...

So what did I do WRONG ??? { 1st time I ever change the master cyl .. so that's new to me }

.............. mark
 
Sometimes it takes a lot of work to get all the air out of the system. I would keep trying unless you see fluid leaking somewhere. It's also possible the master cylinder was defective.
 
Often times if a new master is not bench bled it will have air caught in it that is hard to get out through normal bleeding by using the pedal. Check here.

Greg
Bench Bleeding
 
I am by no means an expert on jeeps or any thing else, BUT, when you changed the master cylinder I think you allowed air to enter the system. So, in my simple mind, you have fluid in the brake lines with air behind the fluid. I think you will have to keep bleeding the lines until the air works down to the wheel cylinders to escape. Are you closing the bleed screw before you let off of the brake pedal? I have had some where it took almost a full resourvoir of brake fluid to get all the air out. Keep pumping and bleeding and adding fluid and you should get it bled. Chris
 
When you bled the brakes did you start at the wheel closest to the master cylinder and work your way to the farthest one away from the master cylinder? Chris
 
Make sure you have calipers installed correctly. If the bleeder screw is on the bottom of the caliper you will never get all the air out, do not ask me how I know. Calipers on 89 F150 can be reversed and work except for very soft pedal.
 

I was told to start with the farthest away ... R rear , L rear , R front , L front .. that's the way I did it ..

But know I see I screw up with changing the master cyl .... I DIDN'T bleed it before mounting it ... so I'm guessing there"s still AIR in it ..

Boy you LEARN a lot from this site ................... mark
 

I'll check that .... any thing a this point is possible ... I'm looking for ANY and ALL things that I did wrong ...

THANKS ................ mark
 
1. Now when you have some one pump up the brake pedal with 3-4 strokes then you bleed them they have to keep holding the pedal down until you close off the bleeder screw so it doesn't suck air back in when they let the pedal back up.
2. Another way to bleed them is to put a clear hose over the bleeder screw and the other end of the hose into a jar with about an inch of brake fluid in it. This way if any chance it would suck back it will suck brake fluid back in and not air.
3. One more way to bleed them is by putting the clear hose on the bleeder screw with the other end in the jar of brake fluid. Open the bleeder screw and let gravity flow the fluid and air thru. It takes a little longer but you'll be amazed.
4. Now I have seen people replace brake wheel cylinders and put the brake line on the top hole and the bleeder on the bottom hole of the wheel cylinder. You'll never get the air out of the cylinders this way. I saw a mechanic one time put on a set of brake calipers and he was in a hurry. He put them on the wrong side of the vehicle and that put the bleeder screw on the bottom side. He never could get the air out until I told him what he did wrong. Then he told me "I'd like to see you put the calipers on this fast". What an Idiot I thought. I know everything I have said here may make you feel dumb. I don't mean it that way. I thought if you never heard of bench bleeding a master cylinder you probably haven't worked on brake systems. Remember the brake system on any vehicle is the most important system on a vehicle. Don't splice brake lines with fuel line or hose. Don't have rubber hoses made up for a brake system. For one thing you won't see any one making rubber brake lines like they make hydraulic hoses on site at an auto parts store. Anywhere from 2,000-6,000 psi can be generated in a hydraulic brake system. It's always 2,000 +. Most people don't believe this. Brake lines are all special.
 
That model cherokee is a little hard because once the master cylinder is in the car its at an angle needs to be flat. also on some models there was a button you pushed on the proportioning valve just under the master cylinder by the frame.
 

THANKS .... And I appreciate everything you said ... and YES I have worked on a lot of brakes over the years .... but never had to replace a master cyl. .... lucky I guess ...

Anyway I DO bleed the way you said ... ... mark
 
I would take the master cylinder back off and bench bleed it. I've never changed out the master cylinder on a Jeep, but in many cases it's impossible to get all the air out of the cylinder on the vehicle, because the cylinder must be perfectly level. Which is why you bleed them on the bench.
 
Trying to bleed a master cylinder on the car is a difficult and time consuming task. You really need to take it off, clamp it down level, and bleed it on the bench. Most commonly, a set of bench bleeding fittings come with a replacement master cylinder. They consist of a couple of plastic fittings that go into the openings for the brake lines and a set of clear pieces of tubing. You first put the fittings into the line openings, attach the tubing, and run the tubing back into the reservoir. Then, you can operate the cylinder with a screwdriver and keep cycling it until the air bubbles are gone.
Also note that if you have anti-lock brakes, and you get air into the ABS unit, it needs to be bled "electronically." That is, it has to be told by a tool to self bleed. If you have air in an ABS unit, it will also cause a low pedal that will be difficult to bleed.
 
ivor from uk throwing in his 2 cents worth
some years ago we had a Vauxhall brava 4x4 pickup and the brake pipe going to rear brakes failed because of corrosion after I renewed pipe I could not get brakes at all after going round each wheel a number of times
what I had not seen was a bleed screw on the load sensing valve when I opened this a lot of air came out and after going around each corner again the brakes were ok
 
Mark, are you doing this with two people? You didn't say. One person opens the bleeder on the caliper or wheel cylinder a little, one person sitting in the seat pushes down on the peddle and just before gets to the floor, the person at the bleeder at the caliper or wheel cylinder closes it? Then bring the peddle back up, open the bleeder, repeat as many times as it takes until the fluid without air makes it out the bleeder? Then move on to the next, starting as you said the furthest away? I'm just asking. That's the way that I've always done them...two people working together. I have an '01 Cherokee, the barn Jeep but I'm not at home and can't get to the repair manual. There might be something odd about a Jeep Cherokee in the manual, but brakes are hydraulic and hydraulic is hydraulic in my mind. My Ram pickups with ABS have an odd block between the master cylinder and the four wheels, and maybe the Cherokee too, but I can't say because I'm not at home.

Mark
 
Sorry Mark, my Cherokee is an 00', last year made. But it shouldn't matter, i wouldn't think.

I've only ever done one brake by myself, on my '95 Ram 4x4. That was when the line from the master cylinder to the block that split to my fronts brake, broke at the block mounted on the frame. I was by myself, and bent in a new line, and opened the line at the block and let gravity slowly fill it from the capless master cylinder. It worked. When the air bubbles stopped and pure brake fluid came out, that was it. But the line was about 2' long, straight down to the splitter block.

Good luck.

Mark
 
If this has ABS,air can be trapped in the Abs module.May even need bled by someone with a diagnostic computer.You could also try gravity bleeding-just fill the master cylinder ,open all bleeders,and walk away.Keep the master cylinder full.And,when 2 people bleeding,start at the furthest.Mark
 
Can he jack the front end really high off the ground? If not...crazy idea. ABS can be,a total night mare. Also brakes should be pumped SLOOOOOOWLY.... DON'T ask me how I found that one out. Another way is one of those Harbor Freight handheld vacume pump things for like $25.00. Work pretty good but you will be screwed if you let the resevoir run out. One air bubble and you need the diagnostic tool to get it out of the block. Not an expert but I have,been known to screem in frustration.
 

Sounds like you could use a motive brake bleeder, or do like someone on this forum said: Just get a new oil squirt can, put vinyl tube on the can to the bleed fitting, then just pump up to the master.
 
I remember this from an episode of Car Talk. Somebody had both calipers off at the same time and put them back on the wrong sides so the bleeders were at the bottom.
 
My son figured his 05 wrangler out by looking at the sales recite. A left hand part number and a righthand part number and then swapped sides with the calipers. Goes back to the bleed port position on the piston chamber.
 

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