Re: Help! Brake booster upgrade for CJ
I just helped install a booster from a '77 Dodge 3/4 ton van
on my co-workers' CJ7. This is the type that fits sideways under the hood, and is operated by a bellcrank. He picked up a unit at the pick-a-part for $25, exchange, with the master!
The double diaphram booster fits the stock CJ bracket almost perfectly. Widthwise, we had to slightly narrow the mounting holes in the brackets. Height wise, the bolts fit perfectly. The factory spacer on the Dodge is needed to get the spacing to match the CJ booster (approx 1/2" thick plastic, could be made easily). The lines to the master bolted on perfectly, too.
We needed to make a bushing to fit the rod end, (the new boosters' clevis hole is around 5/8ths", the pin on the CJ is 3/8ths"), by using a 1/8" pipe union and boring out the threads to 3/8" we made a perfect fit. A slightly longer clevis pin was needed to connect the linkage as the rod end is wider on the Dodge booster, we cut off a grade 8 bolt with a long shank, and drilled a hole in the right spot for a clip.
The Jeep stops very well, the job took about 1/2 hour to complete.
The Corvette booster, with a YJ bracket has less effort, but more pedal travel than the Dodge Booster. The Dodge booster has about the same pedal height and travel but much less effort than the stock power brakes, the Corvette setup has a higher pedal, and longer throw, like that of a CJ with manual brakes, but is extremely powerfull. The difference is due to the fact that the Dodge booster uses the original multiplying linkage that the CJ booster had. The Corvette setup connects directly to the pedal arm, effectively higher on the pedal, giving greater leverage, but more travel.
Both boosters with the master cost around the same rebuilt, $100 with a core at the local Autozone. The old CJ booster can be returned as a core later, usually they won't notice it's different then.
Both setups are able to use the stock proportioning valve, I haven't experienced any problems yet.
Hope this helps!