06 TJ Booster & MC in my YJ

**glenn-91YJ** · 03-06-2011, 05:23 PM

Well with the 33s and added weight of bumpers and winch I really needed to improve the braking. I've seen where guys have installed a 95 double diaphragm booster. Problem is trying to find a used or even a new one.

So I looked into the difference between the TJ booster and the 95. The main difference is the length of the diaphragm rod. Here's a side by side of the original 91 and the 06 TJ boosters. There were two other things, the mounting bolts which are #10 metric bold requiring the mounting bracket will be drilled to accept them and lastly the brake lines come off the master cylinder on the opposite side...no big deal.

The 91 booster rod eyelet measure 7.5" off the back and the TJ measured 5.5". So to make this work I needed to lengthen the rod a couple inches. To start I cut the eyelet end off with about 1/4" of shaft length.

I then took a 1/2" coupler and drilled it out to 1/2" on the drill press. I cut a 1/2" length to be used as a coupler to weld the pieces together. Here's the finished product. With the threaded 1/2" grade 8 bolt welded to the eyelet I now have an adjustable length rod.

The coupler to mate the two together was drilled out to 1/2" to slide over the booster rod. Here it is the on the booster. The coupler will be attached with a 10-24 grade 8 allen bolt with a nylon lock washer. I'll match drill the coupler on the rod. There are predrilled holes on the coupler which will be used to tack weld it to the main rod. I didn't want to weld the front of the coupler to the rod for fear of potentially damaging the internals of the booster. I figured a couple tack welds through the holes wouldn't get the rod all that hot beyond the coupler. I also have a lock nut that will be used for the threaded section that isn't shown.

Apollo12227 · 03-06-2011, 05:30 PM

The 1995 dual booster for the YJ does the same thing and doesn't need to be modified. Why didn't you go with the 95 setup? Just wondering if there was a specific benefit to a TJ dual booster vs the 95 YJ dual booster. Oops, I just read where you said they were hard to find. My local Autozone had to order one, it took about three days and I used my YJ booster as the core... But used would be a bear to locate.

Either way good mod work! You'll love the dual booster.

**glenn-91YJ** · 03-06-2011, 05:32 PM

For the brake lines I'm going to use the fittings on the TJ lines that came with the proportioning valve. I attached them to my valve until I get the booster back in.

I bought a double flaring kit and a couple lengths of 3/16 brake lines with bubble fitting ends. I'll cut one end off and insert my fittings and then put a double flare on the other end for the proportioning valve.

I bought a 24" piece of tubing to play around with. Here's a test end I did. It's actually pretty straight forward.

I'll bench bleed the MC before inserting the assembly. I'll make the new lines, bleed the brakes and hopefully have greatly improved braking power.

I'll followup as I finish up the project.

**glenn-91YJ** · 03-06-2011, 05:33 PM

Quote:

Originally Posted by Apollo12227

The 1995 dual booster for the YJ does the same thing and doesn't need to be modified. Why didn't you go with the 95 setup? Just wondering if there was a specific benefit to a TJ dual booster bs the 95 YJ dual booster.

Either way good mod work! You'll love the dual booster.

Couldn't find one new or used. Got the 06 one for $75.
I called everyone, Advanced, NAPA, Auto Zone, PEP Boys...no one could even order it.
No luck online either...every site said not available from manufacturer.

Apollo12227 · 03-06-2011, 05:36 PM

Quote:

Originally Posted by glenn-91YJ

Couldn't find one new or used. Got the 06 one for $75,

Yeah my apologies, I went back and edited my post as you were writing this lol... I guess I got lucky my local Autozone was able to land me one for about $80.00 in three days.

Nice work though!

**glenn-91YJ** · 03-06-2011, 05:49 PM

Quote:

Originally Posted by Apollo12227

Yeah my apologies, I went back and edited my post as you were writing this lol... I guess I got lucky my local Autozone was able to land me one for about $80.00 in three days.

Nice work though!

No problem. So did you notice a big difference in the braking?

ryan2l · 03-06-2011, 06:11 PM

Good info I spent last week trying to find a new or used 95 booster with no luck. I will be ordering TJ stuff off ebay next week.

**Que89YJ** · 03-06-2011, 08:47 PM

Great info. I have been looking too. I will be bookmarking absolutely be looking at doing this. Thanks. I recommend this for a sticky to the moderators.

**glenn-91YJ** · 03-07-2011, 06:06 AM

Quote:

Originally Posted by ryan2l

Good info I spent last week trying to find a new or used 95 booster with no luck. I will be ordering TJ stuff off ebay next week.

Just an FYI...Here's a site I use to locate stuff locally.

http://www.car-part.com/

**glenn-91YJ** · 03-07-2011, 06:21 AM

Just in case anyone was wondering, there is no problem modifying the rod regarding changing the overall diameter of it with the coupler. The rod simply moves the plunger highlighted in yellow in and out of the booster housing.

**jeep63** · 03-07-2011, 06:39 AM

I ended up have to go on-line to purchase my 95 booster. It was a very hard search. I used the 89 as the core to send back.

Apollo12227 · 03-07-2011, 07:42 AM

Quote:

Originally Posted by glenn-91YJ

No problem. So did you notice a big difference in the braking?

Sorry to get back to you late on this. But yeah the dual booster cut my overall stopping distance nearly in half. Now I can't keep from locking up the brakes lol. But yeah there is a night and day difference once you get the rod between the master cyl and booster adjusted properly... If the rod is adjusted too far into the booster it won't push on the master cyl plunger until the petal is nearly on the floor. If the rod is adjusted too long it will keep the brakes under pressure and they will drag on the highway. Its a happy medium getting the damn thing adjusted, mine came out of the box not screwed out long enough and caused me a huge headache until I found out it was adjustable.

**glenn-91YJ** · 03-07-2011, 08:25 AM

Quote:

Originally Posted by Apollo12227

Sorry to get back to you late on this. But yeah the dual booster cut my overall stopping distance nearly in half. Now I can't keep from locking up the brakes lol. But yeah there is a night and day difference once you get the rod between the master cyl and booster adjusted properly... If the rod is adjusted too far into the booster it won't push on the master cyl plunger until the petal is nearly on the floor. If the rod is adjusted too long it will keep the brakes under pressure and they will drag on the highway. Its a happy medium getting the damn thing adjusted, mine came out of the box not screwed out long enough and caused me a huge headache until I found out it was adjustable.

Seeing mine came as an assembly I should hopefully be all set as far as that goes. I've read other articles where guys have swapped in other MCs and have had to play around with getting that adjustment set correctly.

**glenn-91YJ** · 03-08-2011, 04:21 AM

Had a little time to spend on the Jeep last night. I got the booster rod attached with a 10-24 allen screw and nylon locking nut.

Then adjusted the length of the rod to match the old booster length of 7.5" off the housing.

Drilled the bracket holes out to 7/16" to clear the 3/8" mounting studs. Once it was in place I attached the rod to the brake pedal. It worked out making the rod adjustable, as I increased the length one turn to get the pedal properly positioned.

Once in place I used some spare brake tubing to mock up the new brake lines between the MC and the proportioning valve. I cut the lines that came with the 06 booster to reuse the ends. I put them in place and formed my test lines.

Hopefully tomorrow I'll get the new lines made and "bench bleed" the MC in place before attaching the lines to get the majority of the air out before the final bleeding at the wheels.

**glenn-91YJ** · 03-11-2011, 10:21 AM

Finally got the Booster job complete. Definitely a noticeable difference in the braking! Worth the time and minimal cost.

I used some fittings from a brake bleeding kit I bought from Sears. The black rubber fittings pressed into the MC line holes and I used a couple small clamps to make sure they stayed in place. I cut a couple pieces of hose that also came with it and placed them in the MC reservoir. Once filled, all I did was press the pedal down and looked to see when there were no more air bubbles.

Once the MC was bled I then connected my lines and let some fluid come out down by the proportioning valve to let any air out of the lines and then tightened them up. Wiped everything dry, hit it with a little air and then press hard on the brakes a few times to make sure there were no leaks. Looks like I did a good job making my own "double flare" ends on the lines!

Because I didn't introduce any air into the lines I didn't bleed the brakes down by the wheels. The pedal was firm and Jeep braked better than before. It's something I'll do when I get a chance just to make sure.

Here it is all finished up.