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My main problem with the FSJ booster was two fold.
First, clearing the huge valve covers I had on my engine at the time.
Second, it didn't have enough power to fully push in the MC for enough braking.
And if you have the travel issue like that, are your rear brakes even working?
Almost sounds like a bad MC to me.
Does the fsj pedal move the pushrod to it's full extent? Or can the rod go in a lot further if it wasn't attached to the pedal?
At what point of pushing the pedal in does it actually start pushing out the brake pistons?
I take it you have everything adjusted correctly?
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My main problem with the FSJ booster was two fold.
First, clearing the huge valve covers I had on my engine at the time.
** No problem there. I've got an AMC 360 in there.
Second, it didn't have enough power to fully push in the MC for enough braking.
** The pedal goes all the way until I can feel it bottoming out. I haven't removed the 1 ton MC to measure the stroke (I should have done that BEFORE the install...), so I don't know if the booster is short on travel or not.
And if you have the travel issue like that, are your rear brakes even working?
** I think so. At 30-40 mph, I can get the rears to lock up a bit, but nothing spectacular.
Almost sounds like a bad MC to me.
** I'm going to plug the lines and see if the pedal is hard. The MC is new, from Napa.
Does the fsj pedal move the pushrod to it's full extent? Or can the rod go in a lot further if it wasn't attached to the pedal?
** I'm using the FSJ booster, too. The pedal is able to travel as much as the booster will allow it to.
At what point of pushing the pedal in does it actually start pushing out the brake pistons?
** If I unbolt the MC from the booster and push the pedal down, the MC is pushed out almost immediately.
I take it you have everything adjusted correctly?
** I sure think so. I'm going to try clamping the lines (front and rear separately) and see if the pedal goes hard.
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OK, Hammer found my original post for me, so I'll add my conclusion here, so people searching can see it:
I dove back into the brakes today.
The short version: Use a double diaphragm booster with large bore master cylinders
The long version: Thinking that my brake booster was bad, I swapped it out and installed a double diaphragm booster in its place. Wow. Instant brakes! The truck stops without the pedal going all the way to the floor and it even stops when in low range. I think that as the pads get broken in, they will grab even more. I'm happy. Definitely money well spent. It doesn't stop as quickly as my FSJ, but it's also heavier, too. It'll be nice not having to give my leg a workout every time I drive the thing!
ONE MORE THING: I measured the stickout of both the single booster and the double booster. The double booster has slightly more travel on it. Who knew? This, combined with the extra boost power, I think makes a BIG difference.
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And yet another update for those who care (and even for those who don't, but have to click on the new threads anyway just to see what's posted! :D )
I had the local machine shop cut out the brake drum centers for me to use as spacers, as suggested by Ray, to prevent rubbing of the brake assembly on the wheel. It helped on one side, but not the other. I don't think the fault is with the kit because my wheels are "custom" made from stock OEM centers welded into 16.5" wheels. The weld is a little thick on some areas of the wheel and the brakes rub slightly on those parts. Tomorrow I will grind down the offending areas on the brake assembly. It's around midnight right now and the neighbors might not take kindly to a grinder running right now, LOL!
On a whim, I also tried the top of the line (EXPENSIVE) brake pads from Napa. So far, not much difference, but maybe they need to be broken in, so I can't say much just yet, but at first glance, I'm not convinced that they're $45 better than the cheap ones....
Once that brake interference is taken care of, it'll be time to go wheelin'!!! :)
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Ethan, What did you get the double diaphragm booster out of? I have been curious as well as others about what was going to fix this. My 69 wagoneer has always had a low pedal. I swapped in a dana 60 rear and a dana 44 disc front I darn near had no brakes afterward. I started messing with it by putting in I think a 1 " bore MC. Still low pedal. I picked up a brass proportioning valve but completely tore the rig down for a resto before I put it in. I'll be starting back up on it by fall. Also how much did you pay for the DD booster? It would be nice to have solid brakes again.
Thanks... Al.
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The booster was from an 86 Grand Wagoneer. Sometime in the mid 80's, Jeep/Chrysler (whoever!) decided to put the dual diaphragm booster in most of the FSJ's. Mine was free, as it was part of my Backyard Junkyard that I had when we lived on my in-law's farm.
IIRC, they're about $175-$200 from NAPA.
Whatever master cylinder you use, make sure it's for your style of brakes, either drum-drum, disc-drum or disc-disc. It apparently makes a huge difference.
I'm not real impressed with the 80-91 FSJ master cylinder, since it's actually TWO different sized bores. Go figure. :confused:
RE my 715. I took my grinder to the offending parts of the front brakes and they work great! In keeping with the theory of Jeep Equilibrium (Short Version: If you fix something, something else, sometimes completely unrelated will break), my QT t-case is puking fluid again.
The FUN NEVER ENDS!!! :D
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If there are different sizes, its a disc/drum type...if you have disc/drum it might be ok...if you have drum/drum or disc/disc, it isnt what you want.
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Any Pics? I would like to see some pics of the rear disks, all I have seen so far is fronts.
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I only installed the front conversion kit. www.bigscaryjeep.com
