swapping brake booster pedal rods

[james750]

Looking into the WJ brake booster swap. Is there was a way to swap pedal rods from one booster to the other myself to eliminate the hassle of grinding down a new pedal rod and dealing with the higher pedal?

[cracker]

Looking into the WJ brake booster swap. Is there was a way to swap pedal rods from one booster to the other myself to eliminate the hassle of grinding down a new pedal rod and dealing with the higher pedal?

 

You can swap the rod but there is no need.

 

For 5 minutes of work, redrill out the hole on the WJ rod to the same diamter (as the XJ rod, don't recall the size). Then take your grinder and make the flat spot for the brake light switch. If you grind too much need not worry. Just weld a bead on it and do it again :) This is how I did mine.

 

Good luck.

[johnnyc]

When I did my WJ booster swap, I found that I didn't have to grind the flat spot or enlarge the hole. I had already ground the flat spot before I realized that I did so unnecessarily. :fs1:

 

I'm not sure when they changed the rod/brake switch setup, but in my 92 MJ, the booster was a direct fit. :dunno:

[cracker]

When I did my WJ booster swap, I found that I didn't have to grind the flat spot or enlarge the hole. I had already ground the flat spot before I realized that I did so unnecessarily. :fs1:

 

I'm not sure when they changed the rod/brake switch setup, but in my 92 MJ, the booster was a direct fit. :dunno:

 

Probably cause it is the HO model :dunno:

[james750]

Yeah, but to avoid issues with grinding too deep (don't have a welder), or at the wrong angle,and the pedal being too high. I'd like to swap the rods for these reasons. What all is involved, anyone know the secrets for me to do it myself?

[HOrnbrod]

Yeah, but to avoid issues with grinding too deep (don't have a welder), or at the wrong angle,and the pedal being too high. I'd like to swap the rods for these reasons. What all is involved, anyone know the secrets for me to do it myself?

 

On the 91s and up, the newer booster and rod is a direct bolt-in. You have a 90 model James - modifying or swapping the rod is needed. I've never heard of anyone swapping the booster rods; they always send them off to a rebuilder to do. I suspect it's because the booster shell has to be opened up. I'd try to carefully modify by grinding the new booster rod as many others have done. If you grind too much off, you could always pick up an 91+ HO brake switch, connector, and bracket at the yard, install the new switch and wire it in. The new HO switch rides the brake pedal arm, not the booster rod. The HO brake switch has NO (normally open) contacts (two sets) and "make" when the brake pedal is applied.

[LoTGoD]

The HO brake switch has NO (normally open) contacts (two sets) and "make" when the brake pedal is applied.

 

Is this different on the Renix era wiring? Just curious as I am fighting with no brake lights and a high pedal on my 90 now. I drilled out the WJ rod, and ground the flat spot down, but I am not getting lights when the brake is depressed. I figure I'll get a newer HO pedal assembly and switch and start over.

[HOrnbrod]

Yes, different. One of our members used the HO brake switch in a Renix (Jeff maybe?); hopefully he'll chime in.

[tugalo]

When I did my 90, I ground down the rod a bit too much. I did not get brake lights cause the switch was not actuated. I just made an aluminum shim with a 90 degree bend in it and dropped it in over the brake light acuator switch. The mounting bracket for the switch keeps the shim in place

[comanche09]

Yes, different. One of our members used the HO brake switch in a Renix (Jeff maybe?); hopefully he'll chime in.

 

I used I HO brake switch on my '88 when I converted to the 95 XJ booster setup. Ground the rod perfectly but still couldn't get the brake light to come on right. Pretty crappy design that switch on the Renix era rigs.

 

So... I grabbed the pedal assembly from a H.O. which has the bracket on it to hold the H.O. switch. Swapped my clutch pedal to it (or vise versa, can't remember), then cut and splice the switch wires and now have reliable brake lights. Ugh, I remember what a PITA that was, my back hurts thinking about it.

[smithe1811]

ok, i plan to make this mod in the very near future and i need to be sure of what parts are needed here. do i just need the WJ/XJ(95-96) booster, H.O pedal and brake light switch?

[mfpdm]

Here's a good link that should answer all question about doing the swap using an XJ booster.

 

http://www.madxj.com/MADXJ/technical/te ... pgrade.htm

 

The 96 XJ swap is pretty much a bolt in affair with just a few things you need to consider. You don't need to flatten the rod, just use the later brake switch and put it in the hole that the cruise control vacuum release switch would go. That is unless you have the cruise control. When I did the swap, I also swapped the pedal assembly to bypass using the ID to OD spacer and so I could use the Renix era cruise control vacuum release switch. Just had to do a slight mod to the pedal assembly which you can see here.

 

:cheers:

[james750]

I don't have the bracket for cruise control switch on my pedal assembly. Biggest concern for me is the high pedal. I want to go to a WJ booster because its stronger.

[mfpdm]

The bracket for the Renix era pedals is a bolt on. Just pick one up at the JY when you get the later brake switch. Pic below you can see the screw holding it on at the left side of the pic.(right side of actual pedal assembly)

 

 

As far as the high pedal goes. Most the times I've read about this was because the person either used the wrong year booster or forgot the spacer plate that goes between the booster and the firewall. I've not had personal experience with the WJ booster, but according to the link below, his ended up lower. :dunno:

 

http://www.4x4wire.com/jeep/tech/brakes ... 3/booster/

 

:cheers:

[james750]

Awesome, could you tell me the size of bolt head that is holding it on. I am assuming it is an 8mm (5/16ths) or a phillips screwdriver. Need to know so I can take the right tool and just pull it out after work on my way home.

[mfpdm]

Awesome, could you tell me the size of bolt head that is holding it on. I am assuming it is an 8mm (5/16ths) or a phillips screwdriver. Need to know so I can take the right tool and just pull it out after work on my way home.

 

You made a good assumption. It's an 8mm(5/16th will work). :thumbsup:

 

One thing to check. My pedal assembly is from an auto so look at yours to see if the holes are there for it. Should be but better safe than sorry.

 

:cheers:

 

EDIT: Just looked at the manual pedal assembly I have and the holes are there. Also learned why it has two holes for the switch. The right one is for manual and the left is for auto. :D

[james750]

Cool, I was curious as to why there was two hoes as well.

[comanche09]

EDIT: Just looked at the manual pedal assembly I have and the holes are there. Also learned why it has two holes for the switch. The right one is for manual and the left is for auto.

 

Yup, I pulled the pedal assembly from an automatic, just moved the switch over. With both pedal assemblies on the bench, I was able to swap my clutch pedal to the automatic assembly. Be careful pulling the switch out of that hole, I partially stripped the plastic switch threads and have it backed up with a zip tie in case it decides to pop out...

 

If you are going to re-use your prop valve, don't forget you'll need brass adapter fittings (easily found at your local parts store) My front brake hoses were seized to the line fittings so I ended up replacing the front lines.

 

Great mod though, you'll get modern braking performance.

[james750]

I plan on re-using the original nuts on the MJ lines at the prop valve. Then I plan on getting the WJ lines, cutting the prop valve end off, putting the MJ nuts on and re-flaring that end. I don't want to reflare the WJ master cylinder side of the lines because I don't have a bubble flare fitting, only a double flare fitting for my flaring tool.