Spongy Brakes

[ekaybe]

I've replaced the Master Cylinder (which was leaking), front hoses, calipers, and the wheel cylinders. Brakes are bled well and the rear brakes are adjusted properly, yet I still have a spongy pedal. Anybody ever dealt with anything like this?

[xj-jake]

Emily, if I recall correctly the D35 in the 99 has ABS correct?

If so it may be necessary to bleed the air out of the ABS module on the left fender in front of the master cylinder where all the brake lines run out of. To do this you will need to take it in to a shop and have them cycle the module with the DRB scan tool then re-bleed the entire system again.

[nickyg]

I have a 96 with no abs. I had spongy brakes untill I changed the flushed the fluid out. I didn't have a helper so I bought this thing. Not sure if this is your problem or not but this was it for me.

Amazon.com: Motive Products Power Bleeder Fits late model Chrysler vehicles: Automotive

[ekaybe]

My XJ does not have ABS. The system has new fluid and has been properly bled.

[4.3LXJ]

Then I stand by the rubber line theory. You didn't mention the rear line

[ekaybe]

I have not replaced the rear line. Might do that tomorrow.

So a little food for thought here. Typically when a vehicle is off you have to pump the pedal in order for it to become firm. Well this one is always firm. If you have the vehicle running with the pedal to the floor and you shut it off it the pedal actually pushes your foot back up and becomes firm.
I've never had brakes behave this way and I know my other Cherokee didn't do that either.

[bluedragon436]

I have not replaced the rear line. Might do that tomorrow.

So a little food for thought here. Typically when a vehicle is off you have to pump the pedal in order for it to become firm. Well this one is always firm. If you have the vehicle running with the pedal to the floor and you shut it off it the pedal actually pushes your foot back up and becomes firm.
I've never had brakes behave this way and I know my other Cherokee didn't do that either.

I'll have to take a look at mine and see what it does in those situations.. I don't so much have spongy brakes on mine.. but I do feel that they don't perform nearly as well as they should... and like you, I know they don't perform nearly as well as my 98 XJ did..

[4.3LXJ]

I have had the pedal come back at me when turning the engine off. It is due to loss of vacuum I believe. The rod on the pedal does not go directly into the master cylinder. The rod on the diaphragm does that