Power Booster Mounting

So what would be a good hanging pedal donor? Or if anyone sells them?

 

Are their any other donor pedals I could rob from or anyone sell some I could purchase? Or could I cut the pedals down and rebore the holes?

 

Lots of us use the Jeep OEM pedals from various years and modify..............Lots of smaller options in the junk yard...............what works is whatever you can fit in there and attache the correct Hydro cylinder & master cylinder to............and get the correct pedal ratios........and floor clearance..............some of the guys with the smaller flat fender Jeeps use Willwood aftermarket pedals........... Unfortunately no easy solution as one size does not fit all................Most important to gather up what your doing for Brakes first..........Discs , drums / Disc & Discs and work backwards.....Booster like I said ........stay with and 8" vs the larger 9"..........clearance and making everything fit will be trial & error so plan ahead and don't weld or drill holes until you can see the light.....

 

Those pedals are fine to start with..........but they will need some mods.

 

Yes I have disks already mounted. I was thinking of purchasing a new booster, so I should work from the engine bay to the pedals is what your saying. So one thing. Is that plate you installed behind the booster there for support or what and is it welded in? I was going to cut one and do something similar to yours.

 

What I'm saying is get the master cylinder , booster & proportioning valve ( if required as some masters are already set up internally to accommodate the proportioning) and your hydro clutch master cylinder and have all those parts that are correctly matched to your Disc brake & clutch system in hand before you start to lay things out on the firewall side..........all of which will be important for size & clearance purposes.

Small is better room wise and that is why I would use the 8" dual booster vs say a 9" booster although they do even make a dual 7" booster.......but since brakes are important off road and normally used allot the dual 8" is a good size vacuum volume wise and still fits fairly easy on the firewall.

The plate behind the booster is .125 steel material that can be welded.......although I was going to Huck Rivet that one , but I would just bolt it through the sheet metal using 1/4" bolts and some large fender washers or a duplicate plate on the other side to sandwich the firewall..........that should give you plenty of strength as long as you add the vertical brace on the dash side of the pedal bracket...........that consists of two plates......one welded to the pedal bracket that has slotted vertical holes for adjustment.....and the other welded to the cowl above where that strong rib is ...............that bracket will stabilize the pedals and not allow for flex in the firewall when applying foot pressure.

Also if you look at the center of my pedal bracket , I replaced that center plate for two reasons........1) the pattern on the OEM pedal plate fits the Master only pattern and not the booster pattern.....and ....2) I moved the booster center hole down some to help it fit better while also correcting the brake pedal ratio to the existing pedal arm........

This may all seem confusing and somewhat challenging but just think it through and take a step at a time and you'll be fine.........if you have more questions were all here.


Pedal Ratio:

 

I follow you. Did you use a mounting bread key for your booster?

 

It's early........Not sure what your asking?

 

I went a little different route. Hanging brake pedal/booster from a Cherokee XJ but left my original clutch pedal. As Tarry mentioned you need to make sure the pedal has full travel. My pedal was hitting the floor and I was not getting full travel and of course terrible braking.

 

Meant to say mounting bracket for you booster to the firewall

 

In that application the booster is mounted directly through the .125 plate on the engine side of the firewall and into the new plate that is welded into the old pedal set................the normal master cylinder bolt pattern is different vs the Booster pattern.

 

Another alternative for a brake booster is a hydroboost unit, especially if space is concerned. I feel they are a superior brake system in every way, YMMV. I
suppose it all depends on your individual needs and abilities. Since I had already converted to Saginaw PS I had the pump brackets and just substituted the correct hydroboost pump. The most common issues I see is not maintaining hose sizing, configuration, and incorrect bleeding procedures. Hydroboost units are commonly available on many GM trucks and some heavier Ford products, I got mine for $25 including pump, hoses and hydroboost unit, if you are concerned about buying a used HB unit, a rebuild kit is about $31. I also think it is preferable to cut off the pedal end of the pedals if necessary to shorten the pedals IF NO OTHER MODS ARE NECESSARY. This maintains the factory strength and engineering, and involves less fabrication. Good luck!
PS I have 3 CJ suspended pedal sets and a couple of the Cherokee (XJ) vacuum boosters, if needed. I don't want to ship from Alaska to Texas in an upcoming move.

 

Would any booster work. Most I find are with brackets. I have space the bracket would just push it out more and may run into my PS pump. Unless I mount the MC off the booster.

 

I may take you up on that if your booster is 8” I have a 9” so it may be tight. Summit sells mount, booster and MC all in one piece but don’t need all that

 

Dual Diaphragm 8" Power Brake Booster Gold Zinc Universal Hot Rod Universal GM | eBay You still need a master cylinder of the right bore size to supplement your brakes.............If you get the right master it doesn't need a proportioning valve.............unless you want something that is adjustable?

 

Thanks Tarry! Yea I already have a Proprtioning valve. Keeping drums in rear and disco up front so the PSI will be different. I was looking at my pedal assembly too. I know I will have to bend them into position but I also thought I could cut th weld off the pedals and cut the length down, grind, and reweld the pedals back on. Or try to get a CJ pedal assembly.

 

There is no CJ pedal assembly other than what you have.........the hanging swing pedals all took place in 72 when AMC took over........and from that point through the eighty's other than some minor bracket changes.......the pedal length is pretty much the same..........you can bend the clutch pedal arm like I did over and down and get it very close to where it needs to be without cutting or welding it. ( I did that in my hydraulic press using a few bending dies , an old V-block will also work)

............the brake pedal is a little more challenging as there is just not allot of room between the column and accelerator pedal.............That arm can be cut and moved over and welded back no big deal..........Again after 72 they moved the column up several inches into the dash which helped that area................just have to start at the top , get your pedal bracket , master and booster in the best position possible.........then come inside and make your pedals fit your liking............it's all compromises you can adjust or move either side........just don't drill any holes until you know everything looks like it will fit...................neither side is perfect.

 

There actually 2 different sets of CJ hanging pedals. '72-'75 which used a narrow stamped support bracket with cast pedals (at least all the ones I've had were cast) and '76 and up with the wide mounting bracket and stamped/welded steel pedals. The latter carried up through the end of the YJ Wrangler with minor bracket changes (addition of hydro clutch master cylinder support bracket). The '76 up are definitely easier to work with.

Tarry99 and others have covered the rest very well.