[klwong1]

I recently had a caliper lock up on me so I replaced it and the brake line on that side. I made sure the reservoir stayed full while I bled the brakes, but now I have no pressure in the pedal at all unless I pump it several times.

This is a first for me, usually i've had no problems when doing brakes. I don't think the master cylinder is bad because it was working perfectly fine before i replaced the line and calipers. wtf?

Any ideas on this would be great! Thanks!

[Heap-O-Jeep]

well my first suggestion is to look at your caliper and see if the bleeder is facing upwards i have heard that you can put a left caliper on the right and the bleeder will be facing downward and of course the air will be higher than the bleeder. so it will never come out. now i am not saying that you made this mistake its just something that i heard of on cherokees thats possible to happen. when sommeone isnt paying attention to what they are doing namely the parts store clerk that looked up the part or the guy packaging the part at the reman facility. if this isnt the case i would let the caliper gravity bleed for a while. then see what happens. also if you are doing the pump it up method and your assistant is pushing the pedal to full travel when you have opened the bleeder there is a possibility that the cup seals in the master cylinder can get cut by going past the orifice holes that they are forcing the fluid into. if bleeding the Entire system does not correct the problem and you have the correct caliper, i would replace the master cylinder. it does seem coincidental for it to just fail at the time that you replaced components.

[klwong1]

The bleeders face into the jeep (towards the engine) but are located on the bottom portion of the caliper. Does that qualify as backwards? I could have very well done this without thinking about it. I was having my BIL gently push the pedal to the floor when I opened the bleeder, and then release after I had closed it. Crap...

[xJoshxx]

Do you have ABS?

Cause if u let it get air into it u wont have any then u'll need an ABS scanner to cycle the pump and have ur bleeders open it kinda speed bleeds.

+ i always bled gravity bled my calipers then put then on the rotor then bleed again with pressure.

[Heap-O-Jeep]

yes they should be on the top portion of the caliper ill bet you put them on the wrong sides. and not to refute what josh had said but i have never have had to use an abs scanner to bleed the abs pump by cycling it. if the valves havent moved in the abs pump there is no reason for air to be in the abs valves unless there was air inthe normal system and the abs system was activated which is unlikely. switch your calipers and bleed again and then see what you got. also your bleeding method is how i do it... but i make sure i only have my assistant push half way or you could put something between the floor and pedal to prevent total travel. i like to gravity bleed before i use an assistant just to get the flow rolling. you would be surprised how much air gets out of the system with gravity bleeding.

[klwong1]

I knew I'd end up doing something retarded when i did this! I need to drop the Jeep off to have the inner axle seals on the front diff replaced. The shop is only a few blocks away, would it hurt it if I (very carefully) drove it down there "as is" and just had them swap the cals and bleed the whole system since they have to take all that off anyway to pull the axles and replace the seals?

[Heap-O-Jeep]

thats up to you but i would get satisfaction in a job well done by fixing it myself before taking it to them and risking a wreck and embarrassment. thats just my opinion.

[xJoshxx]

Originally Posted by Heap-O-Jeep

yes they should be on the top portion of the caliper ill bet you put them on the wrong sides. and not to refute what josh had said but i have never have had to use an abs scanner to bleed the abs pump by cycling it. if the valves havent moved in the abs pump there is no reason for air to be in the abs valves unless there was air inthe normal system and the abs system was activated which is unlikely. switch your calipers and bleed again and then see what you got. also your bleeding method is how i do it... but i make sure i only have my assistant push half way or you could put something between the floor and pedal to prevent total travel. i like to gravity bleed before i use an assistant just to get the flow rolling. you would be surprised how much air gets out of the system with gravity bleeding.

What i meant was If you let the Reservoir get an air pocket in it that's bad.

BUT if u want all the brake fluid out even the lodged nastys the abs works great at pumpin thoose out.

[klwong1]

I'm at a loss about the ABS thing, if it was affected wouldn't the light come on? Thanks for all the input everyone! I'm going to do it tomorrow and give you an update when its all said and done. You all have been an extreme help and I will do my best to help in the future.

[klwong1]

Woohoo! Got the calipers back on correctly, bled them and they work great! Just got the Jeep back from the shop today for the inner axle seals and it drives like a charm! Thanks for everything everyone and I'm sure I'll be posting again soon.

[StillinSaigon]

Originally Posted by klwong1

Woohoo! Got the calipers back on correctly, bled them and they work great! Just got the Jeep back from the shop today for the inner axle seals and it drives like a charm! Thanks for everything everyone and I'm sure I'll be posting again soon.

Next time, screw the ABS System...you're getting too complicated. First off, the post of calipers being upside down is a valid one. When replacing the caliper, make sure the bleeder screws are at the tops of the calipers. Gravity bleeding is the next step by opening all four of your bleeder screws until they're dripping pure brake fluid and as each one drips with no problems, lock the bleeder down until all the bleeders are dripping normally while watching the master cylinder level. One thing I didn't read above is whether your new brake pads were seated against the rotors or not. That will cause a "dead" pedal as well even though the brake system is without air.

Since I work alone, I bought a pressure bleeder for my '87 BMW convertible to change the brake fluid out once a year. I got it through Bavarian Auto.com.

Now that your brakes are working, you need to find out what caused the caliper to lock up. Brake fluid, albeit DOT 3 or DOT 4, absorbs all the moisture in the air and that's where rust and contaminants enter your braking system. Find out from your Dealership as to whether they re-bled the system with a pressure bleeder or just used your brake fluid. Your brake fluid just being open to the air will absorb any type of humidity in the air and one day this problem may occur again from contaminants inadvertently put into your system. The pressure bleeder I have is a "closed" unit, so no air or contaminants get into it.

The Piston within the calipers of long ago were made of steel causing caliper lock-up. Whenever I had a vehicle come to me and had to over-haul the caliper, the new caliper overhaul kit came with Bakelite pistons or hard corps resin instead of metal to prevent rust formation at the piston and caliper with the 3 seals to keep it all together.

Sorry if this makes no sense to you...I'm on my 1st cup of coffee.

~Stillin~

[92cherokeelimit]

Originally Posted by StillinSaigon

Next time, screw the ABS System...you're getting too complicated. First off, the post of calipers being upside down is a valid one. When replacing the caliper, make sure the bleeder screws are at the tops of the calipers. Gravity bleeding is the next step by opening all four of your bleeder screws until they're dripping pure brake fluid and as each one drips with no problems, lock the bleeder down until all the bleeders are dripping normally while watching the master cylinder level. One thing I didn't read above is whether your new brake pads were seated against the rotors or not. That will cause a "dead" pedal as well even though the brake system is without air.

Since I work alone, I bought a pressure bleeder for my '87 BMW convertible to change the brake fluid out once a year. I got it through Bavarian Auto.com.

Now that your brakes are working, you need to find out what caused the caliper to lock up. Brake fluid, albeit DOT 3 or DOT 4, absorbs all the moisture in the air and that's where rust and contaminants enter your braking system. Find out from your Dealership as to whether they re-bled the system with a pressure bleeder or just used your brake fluid. Your brake fluid just being open to the air will absorb any type of humidity in the air and one day this problem may occur again from contaminants inadvertently put into your system. The pressure bleeder I have is a "closed" unit, so no air or contaminants get into it.

The Piston within the calipers of long ago were made of steel causing caliper lock-up. Whenever I had a vehicle come to me and had to over-haul the caliper, the new caliper overhaul kit came with Bakelite pistons or hard corps resin instead of metal to prevent rust formation at the piston and caliper with the 3 seals to keep it all together.

Sorry if this makes no sense to you...I'm on my 1st cup of coffee.

~Stillin~

So if i have my rear brake shoes adjusted too tight to the drum this could cause my pedal to be weak.? or ?