Well....just for s&g I googled WJ booster/master and came up on the deadjeep website. for $36.00 I get a 99-04 Grand Cherokee WJ Power Brake Boost Booster delivered. For $36.00!! I figured wth...so that's on the way. I'll see what I get from that.

Get the flexible lines coming out of the master also.

I did ask cruiser54 but they weren't pictured so who knows. Worst case is I have to make my own.

That's a great price. I've been wanting to upgrade my 89 MJ to a nice dual booster. I already have discs in the back from a 92 Crown Vic. I'm too lazy to google at the moment. Anyone recall what years were a straight bolt-in or minimal mods?

sorry for the huge pic But remember where I said I didn't have any leaks?? Well the sharp eyed will spot the wet brake fluid on this leaf. This is what I found this morning. It turned out the rear line on the prop valve was about half a turn loose. So fixed that and vacuum bled the rears again. Brakes are better. But the pedal still goes to the floor with a whoosh form the booster.


So I think I'm done for a bit. I'll work on it some more in the next few days. The plan is to remove the master cylinder AGAIN and extend the actuator rod as much as I can and see what that does. Then I'll bleed the brakes AGAIN and hope for the best.

If you don't have the lines that go with the master cylinder, you have to be able to make a BUBBLE flare.

Ok. So I went out yesterday and figured I’d try extending the actuator rod. I measured it at about 82mm. I was able to extend it to 100mm. But I did add a jam nut on the end to help support the extension since it was a bit wobbly. That helped a lot. Brakes are right there at the top but they feel kinda odd. Almost no progression. When the pedal is pressed the brakes are right there and pushing further doesn’t change much. It doesn’t go all the way to the floor anymore but lockup takes a hard push on the pedal. And I think my rear brakes are dragging since they were much hotter than the front after a trip around the block.

So I’m gonna pull the rod back out and run in in somewhere between the 82 and 100mm length and try again. Worst case is I get exactly what I had initially.

And after that I think I’m just gonna wait till the WJ kit gets here and see what I can do with that. This combination just does not want to work for me. At least not to my satisfaction.

If it were adjusted too long, the brakes would be on all the time. That's if the booster were good though.

If I could suggest the ultimate brake bleed for non ABS. Take each caliper off, turn it upside down. Have someone pump up the brakes while you hold it. After the piston comes out, use a disc brake tool to force the piston back while upside down. All the air will be forced back through the line to the master cylinder reservoir. Remount caliper and do the other side. Repeat at the other end of Jeep. This works even when the master cylinder is not bench bled

The measurements suggested for determining the rod length are quite convoluted. I used modelers clay, just a small ball and let the rod squish it up against the piston. Cut a small piece of kitchen shrink wrap to put in the bore before the clay to help retrieve it. You can then measure the thickness of the clay. It came out the same thickness the math suggested. Hitting the clay with a shot of keyboard cleaner to freeze it helps keep its shape as you try to pull it back out of the bore. I used a hooked dental pick to get it back out.

Yep. Easy to simply test the booster too, engine off and then engine on.


(But having said that, in my case my booster tests fine according the 'field' tests but still makes a whooshing wet sponge sound...)

Typically a bad booster would give a hard pedal, the opposite of what the OP has. Brakes to the floor are more often leaks (of any kind) or air.

Did you ever get the booster? I tried ordering one 3 weeks ago and never got a shipping notice. I emailed them this morning and got this reply back. I'm guessing that despite the pictures, they don't actually pull the parts until someone places an order. In which case the picture on the site is probably not the actual item you're getting. Looking at Google Maps, they're a really small outfit with maybe a dozen cars getting parted-out. I want to give them the benefit of the doubt. I would have appreciated an email that they were backlogged instead of leaving me hanging.I replied that I still want it, provided they can ship before Christmas since I was planning to install it over the holiday break.

When bench-bleeding a m/c, ya have to be careful not to push in *too far*, or it could damage the m/c.

Sorry if this was mentioned in an above post. (sorry, I didn't read every line of every post)...