jtrask

1987 waggy lmtd 4wd

Hey guys,

Yearly inspection resulted in mechanic telling me I need need a new master cylinder and a new brake power booster. ($500.00)

Evidently, some internal thing is leaking and the front reservoir is draining to the back reservoir. New rear brakes three months ago (shop installed) and the front pads are in good shape.

Parts person suggested I replace the check valve as that may cause similar symptoms. Remanned power brake booster is 3 weeks out- quicker if I pay freight.

Do I need to replace both mc & power brake booster with new/remanned?
Is this reasonably easy to do, or do I need to let the shop do it?
Is there a write up?
Is there something else I should be investigating?

Thanks in advance!
Jan

caged

may as well upgrade to the dual diaphragm booster.

hankthetank

are your brakes spongy or really hard? hard usually means the booster is toast, soft could be the master...

jtrask

The pedal is traveling a while before engaging, other than that the Jeep is stopping well. I'm guessing both the booster and the mc need replacing.

How does the replacement of either or both rank as far as difficulty?

Tips, tricks, or words of wisdom are appreciated.

jtrask

O'Reilly's will have the mc/booster in this afternoon.... everyone else was weeks-months out.

What size flair wrench do I need for the mc?

Do I need to drain the brake fluid before I start this? If so how?

How much new fluid should I pick up?

Are there any tips or tricks to this? I have the Haynes book, but I have not worked on the mc or booster before.

Lowrange2

500!?!?!?

It takes maybe an hour to swap out the MC and brake booster...

Remove the brake lines from the MC, remove 4 nuts from the booster on the inside of the firewall, remove the rod from the pedal and slide it out.

Bench bleed the new one, slide it in, bolt it up, bleed the brakes.

Done.

Lowrange2

Didn't read this but maybe it'll help.

http://www.ehow.com/how_7840299_inst...-boosters.html

No, don't need to drain the system.

How to bench bleed.

http://autorepair.about.com/od/fixit...ench-bleed.htm

jtrask

Wonderful- thank you!

Do you use a flare wrench on the brake lines or just a regular wrench?

jtrask

I cannot get the brake lines to the mc loose. Suggestions?

Already soaked with PB Blaster and no luck.

Tried a pipe for leverage, but came close to mucking up the flats.

What should I try next?

hankthetank

crow foot wrenches...thats all i touch brake/clutch fittings with. PB Blaster helps me out too sometimes. Short of that i would attempt some heat maybe.

jtrask

I got the lines off with a combination of flare wrenches and vise grips.

The master cylinder and power booster were purchased combined. Is it possible to install the power booster/master cylinder and use plastic tubing and the brake pedal to bleed the mc before I reconnect the brake lines?

freegdr

yes it can just need a helper to pump pedal while hoses are held in fluid...

freegdr

Might be a little late but have rear brakes been adjusted ever ?