Swapping in newer booster - what adapters???

I have a '91 w/ the Bendix ABS system and it's not working. I plan on putting 33s on this, so I don't want to keep the Bendix system. I'm going to upgrade to a '96 booster b/c it's the larger kind and will also use a '96 master cylinder. I plan on keeping my current lines, but have never reflared before, so I heard that you can use adapters. I found a writeup on MadXJ
(http://www.madxj.com/MADXJ/technical/technicalfiles/ARbrakeBoosterUpgrade/BrakeBoosterUpgrade.htm)
that specified a part # and even showed the adapters (a lil past 1/2 way down). Are these the same adapters that I'll need in order to keep my current lines? How many will I need - 3? (front left, front right and rear) I don't have a "standard" brake system vehicle to look at and it seems that mine has a ton of lines b/c of the booster, accumulator, etc all seperate. Thanks for any help.

no one knows for sure?

I'll tell ya what I did, you may want to do similar:

I went to the junk yard and picked up a booster, master, and pedal assembly from a 96. What I should have also got was the two braake pedal switches as well.

I also found a coolant reservoir bottle from a 4 cyl. cherokee that fits between the fender and the airbox so I could ditch the washer bottle by the booster. If you don't ditch it, there won't be room for the booster.

I didn't use the booster or master for anything but measurements, since I wanted new parts. What I did use was all the fittings of both the junkyard master and my old master and as many lines as I could. I think I ended up making two double-flared lines. Not hard to do, but you'll end up making more than one each, so buy extra tubing till you get it right.

I’ve just completed the swap of the ABS to a standard system on my ’91 XJ. My recommendations are as follows:
1) Gather all the necessary parts before you start the job.
2) Get the pedal assembly & booster from the donor vehicle (‘95 –‘96) with attached proportionate valve and master cylinder (including ISO flared lines) as one unit.
3) Clean all lines, M/C & valve with brake cleaner. Clear with compressed air. Make sure the reservoir, M/C is in good/working condition: rebuilt or replace as necessary (advise based on my personal experience)
4) Get 3/8” thread dia standard brake line union fittings (qty=3) with corresponding standard threaded end fittings (qty=6)
5) I have not been able to find any adapters for my original lines. They are unusual / oversize units from the ABS modulator. I cut and flared as follows:
-Right front line was cut just before the firewall in front of the 90 deg. bend.
-Left front tube was straightened upwards and cut right below the new prop valve.
-Rear line was simply disconnected at the threaded union, next to the steering shaft.
6) Flare the two cut lines (don’t forget to install the threaded fitting before flaring)
7) Temporarily install the MC, valve & the booster on the firewall and make 3 new tubes connecting the prop valve to the old / cut lines. I first made templates out of a wire (coat hanger) and bent my new tubes to match the template. Improvise the routing, as needed. I can post some pics as a guide if you are interested.
8) Install all components and bleed the system.(hint: fabricate or purchase 2 small tubes for M/C bench bleeding)

Notes: Use quality flaring tool. The flaring process is very simple. If you are not familiar, follow the instructions and practice on some scrap/spare tubes.
You can use 3/16” ready-to-use flared tubes available in different lengths at most auto part stores. Hint: I sometimes use a tube, which is very long, and bend a loop in it to make length adjustment easier. Occasionally I have to use excessive force to tighten my new fitting/union in order to stop a leak.

If you move the windshield washer bottle forward 1-inch approx. and drill new mounting holes, it will fit between the air box and the booster.

I found the most difficult part of the swap was to replace the pedal assembly: working under the dash with very little room for the tools.

Hope this info helps anyone planning this swap. I can add pics and provide more detailed info if needed.

x2 the last post, just did the swap with no problems...

to get to the pedal assembly, take out your instrument cluster. then you can directly reach the two upper screws holding the pedal assembly. taking the cluster out takes 10 min tops, saves you some bruised knuckles and a bent back.

the brake lines in the abs version are all longer than needed. so get a flaring tool, cut them back and re-flare them and you won't need any adapters. re-flaring is easy, just do some practice runs on old lines from the donor. also, as said, keep the fittings from the donor and remember which line hooks up where so you'll know later on.

keep on truckin'

Thanks for the help. If you have any pics, that'd be awesome b/c I don't have a vehicle to look at to base this on. I'm using new parts b/c I feel more comfortable that way - don't want to have to redo any of this anytime soon. I already bought the booster and MC. I have a booster/MC/prop. setup w/ fittings from a '91 that I originally was gonna use (junkyard find), but decided not to b/c I'm going to run 33s and feel better w/ the '96. My understanding is that the '91 pedal will work w/ the '96 booster. Do any of you know if the '91 prop. valve will work w/ the '96 setup? Are the fittings that I have w/ the '91 stuff the same too? The only other things that I need to find are the vacuum hose and manifold fitting and I guess the spacer between the firewall and booster b/c the new one from Advance didn't come w/ it. Any idea where I can get that? Think the dealer could order it? I know I could try a yard, but they'd charge an arm/leg b/c they'd have to remove booster/MC just to get to it. Anything else I'm missing?

I agree with you preference to use all new ’96 components. For that reason, I recommend you purchase a new or used ‘95+ proportionate valve. It comes with a matching bracket to your ’96 setup.
The ’96 M/C is made to accept ISO flared lines only. You will avoid a lot of trouble by purchasing ’95+ corresponding M/C to proportionate valve lines: junkyard or dealer, if available. If not, fabricate your lines as needed: SAE and ISO flaring or adapters. At this stage I would not use the ’91 prop valve (can not be sure about the design characteristics and compatibility)

Pedal assembly:
I’m not sure if a ’91 std pedal will work with your ’96 booster. I read in one post that you can move the location of the actuating pin on any (’91 std or ABS) pedal by drilling a new hole in a lower position. If you are not comfortable doing this change, you can purchase a new or used pedal assembly.

Vacuum hose:
The vacuum hose from the manifold to the booster has to be from a pre-’94 setup. It has a “Z” shape. The vacuum port on later models is in a different location on the intake manifold (the hose has an “L” shape). Junkyard or dealer: still few available when I ordered.
Your ’91 should already have the fitting/vacuum port for the booster on the side of the manifold, just below the throttle body. It is covered with a big rubber cup/sleeve.
Verify if your new booster came with the plastic check valve/ vacuum hose fitting

Spacer:
If your ’96 booster is OEM, it should fit on your ’91 firewall without any additional spacers. However, there should be a white foam pad, which serves as a gasket.

Proportionate valve:
-Two top ports: from M/C
-Bottom front port: rear brake line
-Bottom back port: front right wheel line
-Rear port: front left wheel line

I will try to post my pictures sometime tomorrow.

get the brake pedal assembly off a 96 from the junkyard (if you bought the new mc/booster for a 96) to save you the mods on the '91 pedal assembly...

Excellent help once again - I almost ran at the wall head first at full speed when you suggested getting the prop. valve w/ lines from the junkyard. I had thought to call a yard for the valve, but didn't even think about the lines!!! That'll save me a lot of trouble. Just one of those "idiot" moments for me. :banghead:

get the brake pedal assembly off a 96 from the junkyard (if you bought the new mc/booster for a 96) to save you the mods on the '91 pedal assembly...

Click to expand...

You should not need a pedal assembly if you are installing the 95/96 booster/master on a 91+ model. To be sure take a peek at how your existing booster arm connects to the pedal now. If it slides over a stud and is held on by a clip, your existing pedal assembly will work fine. Also, in models w. the auto tranny the booster arm mounts on the left side of the brake pedal, on stick shift models on the right side (or maybe vice-versa; memory??) Just be sure to install the 1/4" aluminum spacer between the booster and the firewall to get the booster arm length right.

if you want to keep the pedal assembly, you'll need to re-drill the hole for the connecting pin. the greater length of the push rod will be evened out by the spacer, but the mounting angle for the booster is different and requires a different pivot point for the brake pedal.

if you want to keep the pedal assembly, you'll need to re-drill the hole for the connecting pin. the greater length of the push rod will be evened out by the spacer, but the mounting angle for the booster is different and requires a different pivot point for the brake pedal.

Click to expand...

I can only speak for myself. I did not have to swap the pedal assembly; the mounting angle was correct with the, same angle as the original booster, same pivot point. I did have the 1995 pedal assembly too, but did not have to use it. My rig is a 1991 MJ w. the AW4. I know a couple of other local guys with 1991 - 1994 XJs the AW4 autos who did the same mod. Same thing - no re-drilling requirement. I did this 95/96 brake mod upgrade over year ago on my MJ and have had no problems. Maybe it's different with the standard shifts? My only experience on this mod has been w. the auto tranny.

very strange...

i have a 91 4.0 auto w/ abs and did the swap not even a month ago. compared the pedal assemblies and found them different.

i don't know the history of my car since i only got it two years ago. and i definitely don't want to call anybody wrong. but i had to change mine...

The pedal confusion is that we are comparing two different things:

The original thread is about ’91 ABS system and a swap to a ’96 standard system.
The ’91 ABS pedal is different and cannot be used, unless you change/re-drill the actuating pin position.
The ’96 standard pedal has the pin IIRC about 1”-1.5” lower than the ’91 ABS pedal.

I don’t have a ’91/'94 standard pedal so I can’t compare. I’m not sure if Gone-postal has one either to compare. I hope this clarifies the issue.

Well, that's an important bit of information to know. I was under the impression that the ABS and non-ABS pedals were the same. Guess I have to pick up a pedal assembly now. Does anyone know what years will work? Anything pre-96? As long as it's non-ABS right?

Well, gonna bring this post back up b/c I finally found a non-ABS pedal and prop. valve w/ the lines that run to the MC. Not too many yards around here and I've been calling for weeks w/ no luck until today. So, I have everything to do this swap and hope to tackle it on Sunday. Only thing I'm missing and it may or may not be needed is the spacer between the booster and firewall.

Earlier in the thread it was referred to as white foam and just being a "gasket" and then later referred as an aluminum 1/4" spacer. So, what is it? I bought my booster from AutoZone and they're meant as replacements, so it doesn't include things that you'd already have such as bolts, nuts, etc. I just don't want to get into this, get half way through and find it won't line up. If it's just a 1/4" gasket, I'll just fab a mousepad or similar, but if it's an actual aluminum spacer, then i guess I need to come up w/ another plan....possibly a piece of plywood?!? Any help would be great b/c I need to come up w/ something by Sunday.

It's both. The white foam gasket goes over the booster studs first, then the 1/4" aluminum spacer. The spacer is just that; it holds the booster out a bit so the booster back end doesn't hit the firewall when you tighten it down. It also seals the booster arm bellows against the booster body. I suppose you coulduse washers as spacers on the studs, but I wouldn't. When I bought my new booster from ebay (the seller was a Jeep dealer) it came with the gasket and the spacer plate.

It's a 1/4" aluminum spacer that fits inbetween the booster and firewall. The white foam thingy is just to seal the booster to the firewall.

-Ron