Brake problem

lobsterdmb · May 15, 2007

So on my new project, the 1987 xj, I got it with a rusted out rear hard line. I replaced the hard line and went to vaccuum bleed it. The reservoir is full, but I can't get the rears to hold vacuum pressure when trying to bleed it. Fluid just trickles out, unlike the fronts which fluid poured out when bleeding. Is the reason that it won't hold vaccuum pressure is that the master cylinder is dry? Do I need to bench bleed the master cylinder? If so how do i do that in the vehicle?

CanMan · May 15, 2007

Sounds like there might be a clog somewhere else in the lines. The way I have bled the MC in the car/truck, is to remove the lines from it and screw in some junk ones that are shortened. Attach some rubber lines to them and route them into a catch can of some sort. Have somebody(or yourself) watch the fluid come out, and fill the MC back up as you pump the pedal.

Does it have ABS?

lobsterdmb · May 15, 2007

no abs

Rob Mayercik · May 15, 2007

Could the proportioning valve be gunked up?

I don't do my own brake work, but I did have a local GM dealer do a cleaning flush (involved running a detergent solution through the system) on my brake system a couple years back (part of a multi-brand dealer, was referred there by the Jeep store when they saw a lot of dirt buildup in the MC), and it made a heckuva difference. I don't know if there's a DIY kit for it, but

Perhaps it's time to replace all the lines, hard and soft, going to the rear - perhaps a soft line could be collapsing under vacuum and pinching off the flow?

Rob

BTW, do you still need that mirror glass? I expect to be doing my mirror conversion the week after Memorial Day, which would have that RS mirror available to you at NACFest.

lobsterdmb · May 15, 2007

Rob Mayercik said:
Could the proportioning valve be gunked up?

I don't do my own brake work, but I did have a local GM dealer do a cleaning flush (involved running a detergent solution through the system) on my brake system a couple years back (part of a multi-brand dealer, was referred there by the Jeep store when they saw a lot of dirt buildup in the MC), and it made a heckuva difference. I don't know if there's a DIY kit for it, but

Perhaps it's time to replace all the lines, hard and soft, going to the rear - perhaps a soft line could be collapsing under vacuum and pinching off the flow?

Rob

BTW, do you still need that mirror glass? I expect to be doing my mirror conversion the week after Memorial Day, which would have that RS mirror available to you at NACFest.

All rear lines have been replaced.... the soft line is stainless steel now. I am going to try to bench bleed the master cylinder tomorrow.

I do still want that glass so that would be cool.

Rob Mayercik · May 15, 2007

Good luck with the bench bleed - hope it helps.

I'll make sure I bring that mirror along with me to NACFest.

Brake problem

lobsterdmb

Just a Lobster Minion

CanMan

NAXJA Forum User

lobsterdmb

Just a Lobster Minion

Rob Mayercik

NAXJA Member #920

lobsterdmb

Just a Lobster Minion

Rob Mayercik

NAXJA Member #920

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