I now have power brakes

[cjnut]

Why I haven't done it sooner, I have no idea.. Easy swap, cheap to do and it works great. I have an 85 CJ w/chevy 350.

First I located the parts from a local fourm and got them at a fair price. Then I went about looking on the net for any tips on the swap and found these http://www.desertcj7. com/yj_brake_booster_upgrade.htm & Terrain Stompers :: View topic - Going from manual to power YJ brakes and indeed they did help.. Cutting and welding the brake rod was done by a friend (damn he's good) I almost hate to keep his work where it can't be seen, then I threaded the the other half that connects to the brake pedal.



Nice looking weld!!!



I also found that the brake line adaptor part numbers that I got the ref. page were not correct so I had to change one of them. I will put a complete parts list at the bottom of this post.

To start the swap I disconnected the rod from the brake pedal then I unbolted the MC from the firewall



As you can see in the next pic there were 4 bolts around where the old MC was. I simply took those out and bolted up the power brake booster mounting bracket.





I then mounted the booster to the bracket, connecting the rod to the brake pedal on the inside. I bench bleed the MC and bolted it up to the booster. I connected the brake lines by first bending them so they will would mount on the opposite side of the MC. tightened everything up, Then hooking up the vaccum line from the carburater for me looks a bit getto, but I will work on that.. Going from small line to 3/8 on the booster. Bled the brakes, adjusted the coupler so the brakes lights don't stay on and your done.





Parts List:

(1) MC & Booster/mounting bracket (pre-1990) YJ
(1) 1/2"x 13 coupler
(1) Napa brake line adapter # 7912
(1) Napa brake line adapter # 7915
(2) bottles of brake fluid
small amount of vaccume line

Feel free to ask questions I left out some detail cuz it seems obvious to me..

Bill

 

[CJ]

That looks great and thanks for the how to! That is a good weld... Someone has a TIG!

Then hooking up the vaccum line from the carburater for me looks a bit getto, but I will work on that..

You should not use or need and adapter for the vacuum line, It should be about 3/8 diameter and should be hooked directly to the manifold, not the carb.

 

[cjnut]

I would love to use the only vacuume port on my intake but it's being used by my Transmission . I had to decide between the carb or split it with the Transmission .... I tried the carb. Not sure if it's a good idea to split it.

 

[CJ]

I would love to use the only vacuume port on my intake but it's being used by my Transmission . I had to decide between the carb or split it with the Transmission .... I tried the carb. Not sure if it's a good idea to split it.

It won't hurt to run both Transmission and brake to the manifold as long as you use a correct fitting / manifold to do it.

I'm still confused as to what you mean by hooking the booster to the carb. DO you actually hook it to the carb or the the throttle plate or the manifold under the carb?

 

[coldwater]

It won't hurt to run both Transmission and brake to the manifold as long as you use a correct fitting / manifold to do it.

I'm still confused as to what you mean by hooking the booster to the carb. DO you actually hook it to the carb or the the throttle plate or the manifold under the carb?

Wouldn't the booster be vacced from the back port of the throttle plate via a 3/8" line? It looks like the adaptor reduces it to a small line, then loops around to the front of the carb..... I r confused a little. Where is the tranny mod valve vacced from?

 

[cjnut]

Wouldn't the booster be vacced from the back port of the throttle plate via a 3/8" line? It looks like the adaptor reduces it to a small line, then loops around to the front of the carb..... I r confused a little. Where is the tranny mod valve vacced from?

You are correct, I have the line reduced to the front of the carb. bottom but not the manifold... The only vacuum port that is on the manifold (edelbrock EPS) is behind the carb., that is where I have the Transmission mod connected too. I just wasn't sure if splitting the booster/Transmission was a good idea.

 

[coldwater]

There's not a throttle plate under the carb with a 3/8 port? Nice job with the brakes though.

 

[Old Dog]

IMO I would use the manifold for the brakes, and use the carb vac. fitting for the Transmission . as it doesn't use a big dia. hose anyway.

 

[cjnut]

There's not a throttle plate under the carb with a 3/8 port? Nice job with the brakes though.

Yes there is a throttle plate with a 3/8 port but the pcv has got that one.. I think I will go brakes to the manifold and Transmission to the carb. and see how that works.

 

[cjnut]

Well I connected the brakes to the intake manifold, and the Transmission line to the front of the carb.. Very big difference!! Tranny still shifts firm like normal, amd now the power assisit works every time push on the brake pedal. It was a little inconsisitant before. I was thinking I need to bleed the master cyl again. Now I can adjust the pedal height and be done.. Thank you guys for your helpful advice..

Bill

 

[CJ]

Great! I didn't think that little 1/4 line could flow enough vacuum and I'm glad they are working fine now.

 

[coldwater]

There you go, It take almost no vac to pull that little tranny modoulator, but the booster has a big ol diaphragm that needs quite a bit of pull to make it work well. Glat you're getting it sorted out.