I just got a 96 XJ dual diaphram booster thinking I could adapt it to my YJ. Its not going to fit. Has anybody found a donor vehicle for a dual diaphram booster for a YJ?

I did the master cylinder upgrade but need more line pressure. I wanted to install the booster for more line pressure.

I am driving a 1991 YJ, 4.0, Auto Tranny.

I thought that a brake booster only helps with pushing the pedal not actually increasing brake line pressure.?

The added volume of fluid stiffened the pedal and decreased line pressure at the calipers. If I boost the pedal pressure I can force more pressure on the fluid at the calipers. I can only move my pedal about 1/2 the way down now.

78 Mercury Marque

I got the master cylinder from that same vehicle. I thought that was a hydroboost vehicle?

Are you saying I can use the vacuum booster off the same Mercury car and its dual diaphram and will bolt up to a YJ?

PS: What's happening with the springs?

It works GREAT with my 4 wheel disc. Bolts on!

The spring should be here around the end of the week.

1tonYJ,

so, are you running both the Merc.Marque booster and master cylinder? and this bolts directly to the YJ booster bracket?

please clarify.

thanks!

matt

Yes please do clarify. Are you running both the booster and the MS from the 78 Marquis? I am already running the MS.

I'm running a booster from mid 80's Chevy G30 van. The mounting bracket holes from the YJ need to be enlarged slightly as the studs are larger on the van booster. I bought the MC from JB conversions as I was short on time. Looks like it's from a Chevy truck but I haven't checked the numbers. The setup works awesome with dual piston Ford calipers on all 4 corners. Still using the stock proportioning valve and the fronts just lock up before the rears. I haven't been in another YJ with anywhere near as good of brakes.

Just the MC from the Marque, the booster is Jeep, proportioning valve is Jeep.

Besides the bracker holes what other mods were required? Did you have to do anything with the pedal rod to connect to the pedal lever? Is the booster rod at the master cylinder adjustable?

Got pics?

Originally posted by Jeeptoy91
Besides the bracket holes what other mods were required?

I had to fabricate a bracket to hold the brake light switch.

Originally posted by Jeeptoy91
Did you have to do anything with the pedal rod to connect to the pedal lever?

No.

Originally posted by Jeeptoy91
Is the booster rod at the master cylinder adjustable?

No

Originally posted by Jeeptoy91
Got pics?

No, I'm not really sure if they'd do any good but I can snap some early next week if you really want them. I think I have one of my engine compartment that may show the booster/MC. I'll look and if I do I'll post it later.

I would like to see the pics of the booster, MS and all installed (side view). I also would like to see how you attached the pedal to the booster rod.

Here's one I had on my computer. Not a really good shot but all I had now. I'll take some more this weekend.

Thanks.