Brakes - Dual Diaphragm Booster Upgrade Write-up

[traitor5150]

Use a Booster and mc out of a WJ 99-05 grand cherokee. With the 1/4 spacer from a late model xj very nice swap mutch better brakeing smaller profile so you dont have the moove your washer bottel on the 87-90 guys and along with a zj prop valve and a rear disk swap I can stop with 35's no prob.

 

[OverlandZJ]

:helpme:

How the hell do you get the clip off the pedal rod at brake lever? I'm having a tough time with this. Cant seem to keep my bad back and fat arse in position long enough..i'm about ready to pull the seat.

:dunce:

 

[Jess]

pulling the seat is the easiest way to get to it.

 

[OverlandZJ]

Got the clip off...but i may have broke the tip where it clips under the pin on brake lever.

I'll concentrate on swapping everything in and bending the lines. Run to U-Pull in morning and grab another clip.

I ended up pulling the seat.

 

[OverlandZJ]

Mine is in but i had a tough time with a few things. The pedal bracket shifted towards the drivers door once i pulled the old booster out. I was able to use a pry bar to shift it back as my son pushed the new booster in.

The new booster came very close to the prop valve, making the line tough to clear. The master seems to sit further forward to my airbox than RockTracXJ's.

I used a 95-95 booster, a ZJ master cylinder and installed the ZJ's prop valve internals. I noticed before that all the ZJ internals differed from the XJ's with the exception of the o-ring...so i made sure i used it all.

Tomorrow i'll pull the master cyl back off and bench bleed it, and adjust the brake light switch if needed.

 

[Bouncy]

Two questions as I am in the middle of this job now.

For the 1990 XJ guys.

Did you run the wiring harness under the booster or over it?

2nd...I stupidly took my old booster out without taking a picture of the brake light switch setup...Anyone have a pic they can post up to show me how it assembles?

Thanks.

 

[Bouncy]

Anyone????

 

[OverlandZJ]

Cant help with the 90's wiring as i cant picture it in my mind.

RockTracXJ posted pic of the brake switch on first page, hope that helps. If not i can take some pics in am for ya.

 

[Bouncy]

Cant help with the 90's wiring as i cant picture it in my mind.

RockTracXJ posted pic of the brake switch on first page, hope that helps. If not i can take some pics in am for ya.

He did post a pic of the switch. I need to see an assembled view.

I took the pieces apart and didn't pay much attention. Basically had hands under the dash but not my head and the pieces fell in the floor.

Realizing there was more than just the nut and bolt...Would like to see an assembled view to get the spacers and bushings right.

As for the wiring...There is harness that goes under the old booster..It has the wires for the washer bottle. Looking like I might have to extend the connectors to get it to work. Wondered if others went under or over.

 

[87xjco]

Just an update to this thread that helped me ALOT!

NAPA part numbers for the 4 fittings are
7936
7909
7818
1442

Sorry I don't know which part number is which but they are...

a 3/16" female to 1/4" male adapter
a 3/16" female to 5/16" male adapter
a 3/16" female to M12 x 1.0 male bubble end adapter
a 3/16" famale to M10 x 1.0 male bubble end adapter

Just like the OP desribed

I also am amazed at how much better the braking is now. I have a HP44 and a Ford 9" and a panic stop would have been real scary before the conversion, now no problem.

Thanks !!

 

[smcdonaldaz]

I thought the idea was to use the 95-96 booster so it was a bolt in swap, as long as you got the booster with the correct part# pedal rod. Which all 95-96 seem to be?

Mines still sitting on the shelf waiting install, i can get you that pedal rod number if needed.

x2 on the '95/96 bolt in. Everything I have read says it's bolt in, but only those two years.

 

[MoFo]

I just finished installing a '95 booster and it was bolt-in.

Unforturnatly, the washer bottle no longer bolts in. The front of the new booster interfers with it. Has anyone found a smaller washer bottle with 2 pumps that will fit here?

I read about the new WJ boosters being thinner, after I already had $100 + invested in the '95 XJ booster, lines and fittings.

 

[Hypoid]

I borrowed my wife's hair dryer and heated up the offending corner until I could push it in. It took a few tries to get the fit I wanted.

HTH

 

[4x4fever]

You can buy ajustable p v valves out of sumit catalogue , the hot rod guys use them all the time

 

[MoFo]

Thanks Hypoid. I appreciate the reply. I was going to give it a shot with the heat gun, but was not sure what type of plastic this is.

 

[smcdonaldaz]

I just finished installing a '95 booster and it was bolt-in.

Unforturnatly, the washer bottle no longer bolts in. The front of the new booster interfers with it. Has anyone found a smaller washer bottle with 2 pumps that will fit here?

I read about the new WJ boosters being thinner, after I already had $100 + invested in the '95 XJ booster, lines and fittings.

I just scored a booster and MC from a '95 for $25. Now I need to get the lines and fittings so I can get this done this coming weekend. Do I need to buy a tube bender or can they be bent by hand? If I need one, where's a good place?

 

[OverlandZJ]

I just scored a booster and MC from a '95 for $25. Now I need to get the lines and fittings so I can get this done this coming weekend. Do I need to buy a tube bender or can they be bent by hand? If I need one, where's a good place?

Most aotoparts stores carry a cheap bender, but i didnt use mine. I just hand bent it all, for the 90* bends you can lay it over a piece of pipe etc to help form.

mojo... could you swap in a later model washer bottle to the pass side?

 

[wolfpackjeeper]

you can put the washer bottle in the fender. And if you grab the lines at the yrad that are on the V8 GC mastercylinder, they are already prebent in the way they need to go, without using adapters

 

[MoFo]

When I got the booster and MC, I also got the proportioning valve attached with lines, so I am good on the lines. I could move the bottle over to the passanger side, but then would have to extend both pump harnesses and both hoses.

Tonight I will lengthen the two-wire harness to the brake differential pressure switch on the prop valve by 5 inches, so I can move the main wire bundle to under the booster. That should make room for the pumps. I already heated the bottle and pushed the corner in about a half inch, so it should clear the bottom edge of the vacuum canister.

 

[smcdonaldaz]

When I got the booster and MC, I also got the proportioning valve attached with lines, so I am good on the lines.

Is there a difference between the proportioning valves found with the older and newer boosters?