Brake questions?

[N8CJ5V8]

Brake questions?

After doing my one ton swap I've never gotten the brakes to work as well as I would like for them to.  I would like to hear from some of you guys that are running fairly big tires on what your brake set-up is.

My real question is do I NEED to go to with a hydro boost brake setup to get this beast to stop now or can I get away with my vacuum boost brake set-up?

I'm currently running an auto trans ,40 inch tire's, four wheel disk brake, Corvette master cylinder, the El Dorado calipers 3/4ton calipers and rotors in the rear and all parts are brand new including all lines (except for the Vacuum booster itself, but it seems fine).

 I've bled the brakes a million times, it'll usually get decent pressure for about the first 100 yards, then they starts to fade away quick to the point where I basically have no brakes and I have to put it into neutral to get it to stop.  This brings me to believe that there is either a small leak (which I cannot see?) or (don't know if it possible) where my front line meet the rear lines (small connection block) is extremely close to my exhaust (less than an inch).  I'm not sure if that?s an issue, maybe it's vapor locking the lines or heating the fluid up really bad???  I'm wondering if I need to spend more time with those two concerns or am I wasting time trying to get this set-up to get my rig to stop?  I heard from a few guys running the same gear that the vacuum set-up should work, but I then I've also heard that there is no way I will get the necessary pressure with the vacuum and that I'll need to go with Hydro boost brakes.  I would really like to keep the vacuum set-up due to the expense of the hydro, but my main concern is that I just need to stop the beast, and right now I cannot and going down hills are down right scary and dangerous.

What do you guys think? Ditch the vacuum and go with hydro or spend some more time on the vacuum.  I don?t need to be able to lock ?em up when going 40mph+, but I need to be able to stop on the trail.  Is anyone with a somewhat of a similar set-up running vacuum and happy with it? Any help would be appreciated, thanks.          

[DavidWymore]

I don't think the vac is a problem, something is wrong. My buddy's buggy on 42s with and auto has manual Wilwood master cyl and works. I'd try Pirate.

[N8CJ5V8]

Cool, thanks David!  I'll try posting up there, that's where I got most of the info from.   I may try messing with it some more this weekend?  What sucks, is that it is seems to get great pressure at home then I hit the trail and it's gone within minutes?   I may try moving the connection block and maybe swapping in another master cylinder?????  I really don't need to fork over another $700+ on a hydro kit.   I've read on pirate that the lines from the M/C could be backwards, Ive tried switching them but they are two different sizes and would need to run adapters to get them to fit? I also read that you can adjust the shaft on the M/C but I tried and I couldn't get it to extend any more????  It's actually becoming really frustrating    thanks again!
anyone else?

[DavidWymore]

Master cyl seals maybe.

You bench bleed it?

Your t-case geared low? Low stall torque converter? That will make it hard to stop. The brakes can't get the engine RPM low enough to "disconnect" the TC.

[N8CJ5V8]

Master cyl seals maybe.  Its brand new, but it's a cheepy from Zatozone, so maybe I got a bad one???

You bench bleed it? Yup. Followed the direction it came with.

Your t-case geared low? Low stall torque converter? That will make it hard to stop. The brakes can't get the engine RPM low enough to "disconnect" the TC.   Stock gears in the TC, yes low stall torque converter.

 Keep thinking

[Mikegyver1]

Check your caliper are on the correct sides. bleeders should be at the top above the brakeline inlets on all four corners (if not on correctly you will have air in ur lines with noway to remove it). If that's all good, I would replace the Vacuum booster. You should beable to lock them up. My chevy pickup had the same problem. VB was bad
  

[DavidWymore]

Yeah, possible VB esp since it's not new.

[DavidWymore]

but I would think that would just make you have to push harder...

[Mikegyver1]

Yeah, my chevy's pedal would start off with brakes then fade to the pedal on the floor. 

[N8CJ5V8]

Check your caliper are on the correct sides. bleeders should be at the top above the brakeline inlets on all four corners (if not on correctly you will have air in ur lines with noway to remove it). If that's all good, I would replace the Vacuum booster. You should beable to lock them up. My chevy pickup had the same problem. VB was bad
   

The calipers are on the correct side and the bleeder is at the top. I'm starting to think it it the booster, after all it is the only original part left, and come to think of it, I really never had great brakes before and it was with the same booster.  I'm going to try to get a new one and go from there... then try another new M/C.  thanks  

[HEEP4me]

Glad to see you around here! I have wrangler booster an MC and 35's and they work great..

[N8CJ5V8]

Glad to see you around here! I have wrangler booster an MC and 35's and they work great..

Thanks, I'm always lurking...  BTW how's your build going ?  Any pic?


I've been reading more about it and several people are saying go with the YJ booster because it's a dual diaphragm booster and my CJ booster is a single diaphragm and it basically bolts in.  I'm going to try to find one tonight...  Did you have to mess with the rod length at all?  and Thanks!

[HEEP4me]

I used the whole assembly, bolted right in.


My build is done, I need to post some pic's. It works awesome!  60 in the rear 44 front with superior axles and HI steer, detroits with 4.56s

[N8CJ5V8]

Do you know what year Wrangler the booster came from?

[jbolty]

YJ had a dual diaphram booster in 1995 only, and I think only 6 cyl that year.  TJs, WJs and a few others have the same dual booster but the brackets and push rod is different. Anything can be made to work though.

I can say first hand that the dual booster is a great upgrade but I had all sorts of booster problems. My original and two more remans were all bad until I found a good one.

[HEEP4me]

Do you know what year Wrangler the booster came from?

I dont remember, I had to replace the booster so maybe I have the receipt.

[N8CJ5V8]

YJ had a dual diaphram booster in 1995 only, and I think only 6 cyl that year.  TJs, WJs and a few others have the same dual booster but the brackets and push rod is different. Anything can be made to work though.

I can say first hand that the dual booster is a great upgrade but I had all sorts of booster problems. My original and two more remans were all bad until I found a good one.

Thanks.

After looking into it a little more, I found that I would have to swap the M/C out if I went with the YJ booster.  I Found a 9" dual booster from an S10 in stock locally that fits the M/C.  I had to cut an re-weld the rod (which I really didn't want to do) but it turned out great so far.  If I could have found a 68 vette booster it would have been a direct bolt in, but I couldn't find one in stock and they were more money.  The holes on the s10 are slightly narrower too so I have to redrill two of the holes.   I'll find out tonight and post up, thanks again.

[N8CJ5V8]

It was the booster, duh.    The s10 booster bolted right in after i cut the rod and I didn't need to narrow the holes.  I haven't gotten to test drive it yet, but I can already tell I have more pedal than ever before.  I'll bleed it once more and take it for a spin this weekend, thanks   

[Mikegyver1]

 
 

[Metal Twister]

makes since now.