Grand Cherokee Master Cylinder and Brake Booster Swap

[mscans]

well, i did this swap, and if someone could please help me, now my torque converter will not turn on. the brake lights work correctly, and i know that when you hit the brakes, the t.c. will cut out, but it seems like it is ready, and it just wont pop on, any help would be great.


thanks-
mike

 

[300$XJ]

I did the swap this weekend on my 93, got the booster and master from a 96 grand. Swapped right in but I had to remove the spacer that everyone says you have to use. With it in there I had like no pedal cause the rod was too short. It was still a little shorter then the stock but close enough all I had to do was adjust the brake light switch. What a difference in stopping power!

 

[FordGuy]

Another way that helps on later model is to cut your rod off of the original booster and then cut the end off of the WJ booster, get the exact length required and tig them together horizontally overlapping by 2.5 inches, not only does it give you the correct pedal, it also corrects the slight angle by welding it to the bottom.

 

[Jeepm@n]

Another way that helps on later model is to cut your rod off of the original booster and then cut the end off of the WJ booster, get the exact length required and tig them together horizontally overlapping by 2.5 inches, not only does it give you the correct pedal, it also corrects the slight angle by welding it to the bottom.

Good idea for guy's who know what they are doing when welding, but some of the welds I've seen on this forum I'd be leary about them welding anything to do with the brakes on my Jeep.

 

[FordGuy]

Good idea for guy's who know what they are doing when welding, but some of the welds I've seen on this forum I'd be leary about them welding anything to do with the brakes on my Jeep.

You are right, but the good thing is that if you overlap the rods 2 inches it will be way stronger than it would ever need to be, and if you don't weld mark it, remove it and run it down to a welder. The fit is excellent this way.

 

[markw]

95-96 XJ booster is a dual diaphram, no mods, just bolt it in.

 

[FordGuy]

95-96 XJ booster is a dual diaphragm, no mods, just bolt it in.

I could not believe how much better the WJ booster is compared with the dual diaphram I had prior.

 

[markw]

Did you swap MC's? Mine will lock up all 4's and it has drums in the rear.

 

[FordGuy]

Did you swap MC's? Mine will lock up all 4's and it has drums in the rear.

Mine is a 2000, have 2006 Ford Sport trac Rotors/Calipers, EBC pads and Ford Explorer rears, It work OK, but nothing compared to when I swapped to a WJ booster and master, now it stops like a sports car.

 

[cherokee chuck]

I had a95 w/abs & just disconected the sensors at the wheels[got this cure from 4 wheelers tech col] but my son also has an abs equipped 95 & we got all the lines to the metering block and the block itself. you just yank out the rats nest of tubing & the abs pump & replace them w/the non abs parts. the m/cyl is the same. we didn't mess with the computer, just left it in place. that type of abs has no place on an off road rig.I don't know if they have a better setup on newer rigs or not. also if the abs pump is good you shoul be able to E-Bay it. they are $250. exch at the local full service boneyards.does anyone know if my recently replaced 87 m/cyl will fit the g.c. booster? this sounds like great upgrade but I hate to replace my new[not rebuilt]m/cyl. & that would solv the brake line issues.

 

[ocalajeeper]

I'm looking to replace my booster to a dual diaphram on an 88 XJ. Are there any options without having to flare my brake lines? Can I just use a 88 Master Cylinder with '95 XJ booster or is it a different bolt pattern?

 

[Jess]

I'm looking to replace my booster to a dual diaphram on an 88 XJ. Are there any options without having to flare my brake lines? Can I just use a 88 Master Cylinder with '95 XJ booster or is it a different bolt pattern?

Flaring and bending new lines sounded intemidating to me also. I had a friend (which is also a mechanic) help when I did the swap and both flaring and bending were very simple. I got a double flare tool from autozone for about $20 and it took about 3 minutes for each flare (4 flares total)---going slowly and carefully. Don't let flaring stop you from this mod. I got a booster/mc from a 99 WJ and now I can lock 35's at any speed and with drums in the rear (for now).

 

[89xj]

Flaring and bending new lines sounded intemidating to me also. I had a friend (which is also a mechanic) help when I did the swap and both flaring and bending were very simple. I got a double flare tool from autozone for about $20 and it took about 3 minutes for each flare (4 flares total)---going slowly and carefully. Don't let flaring stop you from this mod. I got a booster/mc from a 99 WJ and now I can lock 35's at any speed and with drums in the rear (for now).

x2, dont let the bending and flaring stop you. its really not hard to do, just practice first.

you only need to flare one end of each line if you buy a long enough line that already has flares on the end. cut the line in half(or to the needed length), bend the line, install fitting on line, double flare the end. if you dont want to flare the line yourself, cut and bend and take the line to a local garage/napa and have a mechanic flare the end.

 

[MoFo]

I picked up a '95 booster / master cylinder and Proportioning valve today together as a unit for $75. I would like to know the function of the switch on the top center of the proportioning valve. Does this detect a difference between the front and rear pressures and turn on an idiot light?

Could this be used as a brake light switch? It appears to be a low current capacity, judging from the size of the wire, but I could use a relay. I have seen a few posts on here about using a hydraulic pressure switch for the brake lights, but no details. Can somebody recommend a different switch?

 

[xjbubba]

"--- I would like to know the function of the switch on the top center of the proportioning valve. Does this detect a difference between the front and rear pressures and turn on an idiot light? YES

Could this be used as a brake light switch? NO

 

[dellstopjeep]

well Im getting no brake lights with the wj booster pedal rod which is ground down even to my old rod. anyone have this issue? Maybe the original brake light switch took a dump and was magically working before????

 

[xxmidianxx]

Thanks for the refreash on this subject. Looks like another thing to put on my list before we go out again.

 

[bcmaxx]

well Im getting no brake lights with the wj booster pedal rod which is ground down even to my old rod. anyone have this issue? Maybe the original brake light switch took a dump and was magically working before????

You did not grind it in the same position as the stock one. I ran into this. You kind of only have one chance at it. I ended up installing a high pressure switch in the line of the master. it was only ten dollars.

 

[89xj]

well Im getting no brake lights with the wj booster pedal rod which is ground down even to my old rod. anyone have this issue? Maybe the original brake light switch took a dump and was magically working before????

i ground down the flat spot on the end of the rod too much and had to shim the brake pedal switch so it would make contact when i apply pressure to the pedal. this is on my 89 without cruise control so its just a 2 wire brake light switch.

 

[MoparManiac]

I didn't even grind the rod on my ZJ booster...I just took the metal bracket that the switch clips into and bent it forward with channel locks...

Works great for me!