can't stop the 39.5s

[JJacobs]

Hey guys, I need a hand here- I'm trying to get my XJ trail ready but the stock brake master doesn't seem to be compatible with the rest of the braking system. I'm running Chevy 60 front w/ stock calipers and 14 bolt rear with 1/2 ton Chevy calipers.
Of course it's all bled, and bled again- someone said I can take out the spring from the brake distribution block? Didn't work. Different M/C? What bolts up and gets the pedal back for cheap?
Oh it's a trail rig only so I don't care about panic stop stuff, I want it to stop and stay there on hills. 88 LTD.

Thanks-

[cagedxj]

What master cyc. and booster do you have? If it is stock you could try the 95 booster swap, but that may not push enough volume for the 4wheel disc setup. I have also used a ford ranger booster and newer dodge ram master cycl. on a customers rig set up close to yours, but he had 44's. it stopped great! You will need to relocate two of the holes in the fire wall. The BEST opition I feel is a GM Hydroboost. This is what I run in my willys tube buggy, with 38's. It will lock all four tires pretty easy.

[4ward]

F-150 master bolts up, don't know if it'll work for you or not though. I'll know tonight if it works for 4 wheel discs. Of course, I'm running 3/4 T chevy calipers all the way around but I don't think the volume will be much different than yours.

Sean

[JJacobs]

The top end of the brake system is all bone stock 88 vintage. I did try a different m/c after thinking mine was crap, it helped some.
Anybody tried removing the thingamajig in the distribution block or something else to mess w/ proportioning, or is it just an m/c thing..

[CRASH]

I have heard the M/C from a 676-68 Corvette moves a lot of fluid. I think they are the ones form the non-power brake cars.

I use the 80's E-350 ford van Master, and it locks up all four of my 1/2 ton D-44 calipers with ease.

CRASH

[JJacobs]

crash, I just checked on the E-350 master. Ports are on the correct side, does it bolt right up to the booster? Guess I'll find out later..
thanks for the tip!

[cagedxj]

You can also use a 76 mercury marquis master for a car fitted with the 460 and 4 wheel disc. Its like 22.00 and will bolt direct with line adaptors.

[4ward]

That spring you removed is quite possibly the residual pressure valve spring thingy. There's a thread about this a little ways down the page or on the next one. I think we're gonna have to drop residuals and most likely will want a proportion valve. I want a p valve next to me in the cockpit so I can play with brake bias on different up and down obstacles. My buggy will get the wilwood dual mc setup or just the classic vette, don't know which one yet. You got any pics of this beast out there anywhere?

Sean

[TN William]

I am running the E-350 M/C also. The holes don't match the studs exactly but you can drill them out or hit them with a Dremel. You will also need fittings to adapt your stock lines to the larger holes in the M/C.

[JJacobs]

Well I talked to Scott @ Rockstomper and he recommended a 77 3/4 ton Chevy m/c with the hd rear brakes. The ports are on the wrong side but it bolts up. I'll be removing the spaghetti/ brake block and running direct front/ rear with no prop valve tonight.

Sean- there's a pic somewhere but it looks like crap, I'll get one for ya when it's done very soon. Oh yeah- leaf spring front, passenger drop, Atlas 3.8. I have a feeling my built AMC 401 and TF727 might be going in before too long- smog, what's smog? :)

[4ward]

TN, what else did you do to your system if anything?

I think I may go the route Jon is taking if my M/C doesn't do the job.

Sean

[TN William]

Sean, I removed the spring from the proportioning valve. I am running Ford discs in the front (HP44) and drums in the rear (9"). I have my brackets made for my rear discs but haven't mounted them. I didn't have enough brake to hold on a steep hill before the change. Now it will lock all 4 35s up.

[XJoachim]

You're running the 1 ton axles so you should use the 1 ton M/C and hydrobooster. This will really give you stopping power. Those crappy stock M/C and booster are not even adequate for a stock XJ :D

Get the M/C and the hydrobooster out of a K30 (M1008) or something else and slap them in. There was an article in the net about this swap but i can't find it right now but this is the route i will go when i put in my D60 front and D70HD rear later this year.

[4ward]

XJo- some of us run full hydro and don't wanna deal with the massive cooling issues of running both systems off one pump. If I wasn't hydro steer I'd go hydro boost in a hydro second :D

Jon, I was starting to wonder if the 401 was gonna be used. What's up with your buggy, decided to put her on a diet?

Sean

[XJoachim]

Hi Sean,

i will rather put a cooler in there than give up the stopping power. But i doubt that the hydrobooster itself makes such a great difference. I will put a cooler in there anyway.

[4ward]

Jon, are ya done with this yet? Is the pushrod the correct length? My bro has 2 prop valves laying around his house so I went over and stole 'em from him. I just want something simple and quick as I don't have much time for fab work before Thurs.

Sean

[Patriot]

Here's a pretty inexpensive fix, most of us already have the booster necessary.
http://www.akextreme4x4.com/tech/brake/master_cylinder.htm
Stops the 37's on my HP44 and 9" w/ disc great.