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Brake Booster Upgrade

J

jeepsrock

NAXJA Forum User
Location
LA California
So over the long weekend i went to the junkyard and picked up a 95 Cherokee Double Booster, Master Cylinder, Spacer and Prop Valve to put into my 94 XJ.

I would like to undertake this project sometime this week but have a few unanswered questions that searching didn't clarify.

First question is which Prop valve should i use..old or new ?

Will i need to buy 3/16 brake line and rent a flaring tool or will the stock lines bolt up ?

Is the rod bolt hole correct, or should i make it larger ?

Thanks
Pete
 
As long as you have the same number of lines and such, the stock lines should bolt up... stock lines on a Cherokee are 3/16. I'm not sure on the rest.
 
The prop valves are both the exact same. So there's no use swapping them unless your old one is giving you problems. You only need to swap prop valves if you're doing a rear disc conversion because the rear discs require a different amount of fluid to work properly. But as long as you've got the drums in the rear the old prop valve can stay. And the lines should just bolt up. But i'm not an expert on xj master cylenders through the years...
 
nochance9 said:
The prop valves are both the exact same. So there's no use swapping them unless your old one is giving you problems. You only need to swap prop valves if you're doing a rear disc conversion because the rear discs require a different amount of fluid to work properly. But as long as you've got the drums in the rear the old prop valve can stay. And the lines should just bolt up. But i'm not an expert on xj master cylenders through the years...
Click to expand...

To clarify this response...The reason for swaping the prop valve is to get proper fluid for rear disks. No XJ ever came stock with rear disks, so using a stock prop valve from any XJ will give no benifit to rear disks-only a prop valve from a vehicle that is stock with rear disks.

If you are planning rear disks in the future you should get a late ZJ or a WJ prop valve. For now, while retaining the stock rear drums, it is not necessary to change your prop valve.
 
Right, sorry if there was any confusion. Jess makes a good point. Kids now you know why everyone tells you to stay in school lol so you can spell good and write purdy.... But mostly so you don't make a fool of yourself someday.
 
Thanks, so i know understand that either prop valve can be used since they are the same and i am using the stock drums in the rear.

I guess my question is since the old prop valve is position differently than the new one with respect to the master cylinder, do i need to make new lines or do the old ones work ?

Thanks
Pete
 
I picked up a 95 Booster and MC with the spacer and it went in like stock.

I ended up using the stock Prop Valve and bent two new lines to the master cylinder. I had to massage the diver side Brake lines to move the prop valve a little forward.

Thanks guys the difference is amazing.

Pete
 
jeepsrock said:
I picked up a 95 Booster and MC with the spacer and it went in like stock.

I ended up using the stock Prop Valve and bent two new lines to the master cylinder. I had to massage the diver side Brake lines to move the prop valve a little forward.

Thanks guys the difference is amazing.

Pete
Click to expand...

This is what I did because I didn't want to mess with the long lines out of the proportioning valve. I bought two new lengths or brake line that fit the proportioning valve, cut off one end, slipped on the fitting from the new master cylinder and flared it, worked like a charm.

Good luck, it's one of the best upgrades I've done!
 
smcdonaldaz said:
This is what I did because I didn't want to mess with the long lines out of the proportioning valve. I bought two new lengths or brake line that fit the proportioning valve, cut off one end, slipped on the fitting from the new master cylinder and flared it, worked like a charm.

Good luck, it's one of the best upgrades I've done!
Click to expand...

************

Nitpicker on.......

Your brakes are the same old junk they always have been, they're just better working junk.

You've just upgraded the hydraulic system to the junk brakes. Definately a better system upgrade, but still severely limited by the stock calipers/rotors.

Nitpicker off.
 
i have the set up from a 2000 xj in the garage right now but was told it had metric threads at the master cylinder so would not fit. Is this true or can i just bolt that puppy on with some new lines down do my prop valve as in the case above?

Thanks
Dave
 
your right in that i would have to make up some small lines as the outputs are on the other side than the stock ones. But does anyone know the if they went Metric any time between 96 and 2000?

Thanks
Dave
 
I believe the 95-96 are metric, the fittings to the MC were different than my 93. That's why I bought couple pre-made lines and modified the end @ the MC to metric. You can also buy adapters to convert but I didn't want to mess with it. There's a write up here with all the part numbers and pics that I referenced when I did mine.
 
95+ use metric fittings at the MC end w\ a "bubble flare" and the prop valve end uses standard fittings with a "double flare." When I did my 88, I made new lines, but I have been told that the stock lines from a 95/96 will bolt right up.
 
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