Kung Fu Brakes needed E350 swap

[ChEwBaCcA]

Anyone done the E350 swap into their XJ? This has gone around a lil on POR but im wondering if anyone here has done this. Seems pretty simple ....take an 88 single dia. booster and get an early 80's E350 master (which year for the E350 master??? anyone) ...... drill out the mounting holes and your done.

My junk right now has an ABS dual booster and ABS master on it....removed the ABS pump due to swappin out the rear axle to a 44. The ABS master is way small..... I think the pump must have increased the pressure when it was a complete system.

The 92 ABS is a strange bird so there is no master that will bolt to this dual dia unit....been through the whole Rybestos book that has MC's back to the 50's, no luck.

I need to get brakes that will lock up the 33's, no way in hell thats happening now..... Im running drums in the back and D30 calipers up front......

any ideas?

Chewy
PS: not really looking to go w/ a 95+ system because the parts cost is more than the 88booster/E350 combo .....the E350 MC is stocked almost everywhere and is said to be ~ $30, compared to a 97 XJ MC that is about 70-80 at autozone...not to mention an rebuilt Booster for an 88 can be had for about $40 compared to $90-100 for 95-97 Xj dual unit. Also the 95+ system is just OK , while the E350 system is said to be able to lock huge tires on full length axles............

[offroadman83]

I am going to be doing this very soon, and to do so you will need a e350 mc from a 86 year model, at least that is what I have.

Here is a link to the swap on a grand cherokee same thing as we want to do, and has the napa part number in there somewhere!

http://www.akextreme4x4.com/tech/brake/master_cylinder.htm

If you do it first Post up your results, and I will do the same. And by the way the mc is about $30 and I already have an 87 brake booster so it should work good.

[ChuckD]

Has anyone, doing either the booster upgrade or the E350 MC, got there brakes to lock up with 33's and D30 pads/disks?

The only true brake upgrade would be larger brake surface area. I know some have claimed better braking, but from what I've read, it's only better response and not actual lockup. Just thought I'd ask the question.

[Beezil]

The only true brake upgrade would be larger brake surface area

very true, but I know chewys point is, he's not even making good use of the rotor surface he already has!

he needs more power to those brakes.

sorry chew, don't know anything on this, but if you know the "offset" from the mounting flange to the rod on the booster, than you should have a parts-bitch lay a master up on the counter, and measure it.....

if it fits, it fits...

oh yeah, do a search on por

[ChuckD]

Originally posted by ChEwBaCcA


Also the 95+ system is just OK , while the E350 system is said to be able to lock huge tires on full length axles............




The key part, Full Length Axles , don't they come with full size rotors or drums?

[Beezil]

The key part, Full Length Axles , don't they come with full size rotors or drums?

yeah, you KNOW they do.....

chewys "disarmed" abs system is part of the problem......

its weak.....

dana 30 xj rotors have enough surface area to lock 33's......we know this.....

chewy is looking for a 40-dollar solution, and a re-main master willd o that, provided it fits his ample dual diaphragm booster. He will see a huge improvement.

all your points are well-taken, I've bragged to chewy while he was sittin shotgun one time, when i showed him how I could lock up 35" tires front and rear with 12" ford discs and 11" scout drums......

hes not looking for an axle swap.

[ChuckD]

I understand, thanks for clarifying on the D30 parts. Many have not stated their ability, or maybe I haven't ask the right question. :rolleyes:

If D30 brake parts can lock up 33's. Then I will also be looking into a better sytem. My brakes seem fine, but I also have not had to locked them up, but I would like to know that I can.

[ChEwBaCcA]

I saw that ZJ write up and that is the same ABS system my Jeep has .... so using an 88 single dia booster should bolt right up to my pedal w/o needing a rod swap, this is the main reason I want to do this. I want to think the 92-94 ABS system probally used the same pedal assem as the non abs system (hard to imagine DC going w/ a different unit) ....which in turn used the single diaphram booster

If I go to the 95+XJ system the rods are different and it "may" fit but this is a daily driver and I dont have time to be drilling differnt mounting locations on the stock pedal assem looking for the sweet spot.

Beezil is correct when he said "very true, but I know chewys point is, he's not even making good use of the rotor surface he already has!" exactly ...my disabled abs MC is the size of something on a Honda Civic! So it needs to go.

A quick look at my bro's 87 old Cutlass , the last year of the RWD V8, and the MC/booster is huge in comparison to anything stock on an XJ. Basically proved the point that the stock XJ system no matter what, was not really up to snuff from the factory.... I mean how can you design a truck for 5 people, their gear and put in the system they did???

Im just looking for a system that will apply enough fluid power to make the brakes work well ...... The system now is not putting out the fluid required to really work the brakes..... not to mention the MC was not designed to work independant of the pump

Anyhow.....I will be doing this and taking pics and hope to do a write up. I was wondering if anyone out in NAXJA land could shine some light on this.

**** Also , going from a dual dia booster to a single shouldnt do anything but change the amount of force i need to apply to the pedal? correct? It really doesnt do anything to in regards to the amount of *work* the fluid is doing..... If I have to put a lil more effort into the pushing of the pedal in order to get better brakes im all for it.....Im not a 110lb female....is my logic correct?

Chewy

[bradlyw]

i did the 95 booster swap into mine and really, it actually did make a difference. u dont gain any more braking "power", but u can get all the power u need to stop "faster" so u can stop quicker which is the goal of most of us when doing brake upgrades. i could never lock my 31's if i tried with the original setup, but now i can lock them up no problem. i'm sooo much more confident in stopping now. the swap IS direct. the pedal hook on point matches up. u need a brake light switch from a 94 xj to make ur lights still work, that was my only hang up on it. if u need some more info or u run into problems feel free to email me bradlyw@okstate.edu.

good luck bud

Brad

[ChiXJeff]

Chewy, I did the 95 system swap on my 94 a year ago. Complete bolt-up. No redrilling necessary.

BTW, that prop valve is sitting in my garage.

ChiXJeff

[Beezil]

chewy already has a dual diaphragm

[Ed A. Stevens]

Anyone know the bore of the E350 MC?

How does the diameter compare to the XJ bore?

[ChEwBaCcA]

I emailed w/ the guy that did the write up and everything sounds real good...since few have done this here, if anyone. im almost commited to doing a write up to let all know how it goes.

From what the author of the link above said, I will have a far stiffer pedal and will have to work the pedal more.....it wont be soft...which is fine as i stated above.......... he also claims he can lock 36" Super Swampers up w/ no problems.....didnt get into what axles he has, but i think it stock axles and brakes from the ZJ .

Anyhow the rods should match, i dont need to swap the brake light switch out, and life **should** be good.

Chewy

[offroadman83]

Let me know how it went Chew, because like I said I want to do it as well.---Kyle

[rpili2001]

I did a copy of the navajo brake setup using a caddy dual diaphram booster (80's Eldorado) and an F-250/350 MC. I did this to replace the single diaphram booster in my 85 XJ.

There was an article on it a few years ago in 4WD and SUV.

If you already have a dual dia booster then just swap in the M/C. The only modification I made was to add a little tit (can I say that) on the plunger per the article and I needed to bend up one new line from the M/C to the Prop Valve.

Sorry Ed I don't know the diameter of the M/C but 1 1/8 inch is popping up in my head.

Good luck.

[cherokeekid]

Originally posted by ChEwBaCcA
I.

.....didnt get into what axles he has, but i think it stock axles and brakes from the ZJ .


Chewy

HP 30 front and 8.8 rear with discs.

[motorman]

Beezil, you comment that a "disarmed" abs is weak. Why would it be any weaker than the same set up before it was "disarmed"?

[ScottRoz]

I did the "Kung Fu" E350 setup on my 88 XJ.
It wasn't magic for me. There is more pressure required to move the pedal, but I must still have some air in the system or something. My brake setup is better than before I swapped the master cylinder out, but still pretty poor.
I'm running XJ D44 drum brakes in the rear and stock D30 parts up front.
The E350 cylinder is supposed to be 1 1/8" compared to the stock '88s 1".
FWIW, bleeding the master cylinder was a PITA, it seemed to take forever. I ended up fabbing the bleeding lines because the "new approved bench bleeding procedure" didn't work right for me the first time.

Scott

[vintagespeed]

To revive this old thread, what size brakelines are we comparing? Does the E350 van use a much larger diameter brakeline system vs. the XJ? I would imagine so, but dont know. I'm going to do this same swap w/dual diaphram booster, and was considering changing my rear line to a larger ID. Is this necessary?

[ChEwBaCcA]

rpili2001 , My ABS double booster will not accept any other MC....anyone who has ever seen one of these will know why. The bore extends into the booster unlike any MC ive ever seen.

What is involved in doing the Navajo swap? do you know what year eldorado booster you used? This way I can match up the rods......Isnt the one navajo sells w/ an adjustable rod?
What all did you have to do?

Thanks
Chewy

[ChEwBaCcA]

So I guess the question becomes.....what dual diaphram unit will bolt to the E350 and share the same rod style as found on the XJ.......anyone , anyone,

Chewy

[ScottRoz]

That 95 or 96 that people are using should work.
It is dual diaphram and is the old pre-97 style.
I can't remember which year right now, but I'm thinking 96.
Check on MADXJ.com
The article should have an addendum of what year works without modifications for older XJs.

Scott

[Carpenter]

Any late model ('95-'00) XJ booster would require a spacer to make the E-350 MC work. The '95-up master cylinders have a ~1" long extension coming out of the back of them that the pre-'95 MCs don't have. I'm curious to see how your swap turns out. I tried the E-350 swap and it made things worse for me. I conversed through e-mail with the guy in the above referenced POR thread and it baffled me how it made such a difference for him and made things so much worse for me. When I did the swap my pedal was much stiffer and with me standing on the pedal I could barely get the Jeep stopped. I bench bled the MC twice and bled the system countless times and nothing improved. I finally swapped in a '95 MC and booster and my problems were solved. I can now stop on a dime with 34" tires, braking is better than in my bone-stock '00 Chenvy Sliverado.

[Ed A. Stevens]

Originally posted by ScottRoz
I did the "Kung Fu" E350 setup on my 88 XJ.
It wasn't magic for me. There is more pressure required to move the pedal
<snip>
The E350 cylinder is supposed to be 1 1/8" compared to the stock '88s 1".

Scott


The hydraulic ratio from this change (from 1.0" to 1.125") in the master cylinder is going the wrong way, to requiring more pedal effort (due to lower line pressure for the same foot force). This is why the braking demands more pedal pressure for the same force on the pads and shoes.

The size of brake hose lines have no impact on the line pressure (unless the old lines are kinked flat and block flow).

Anyone find a 7/8" bore master cylinder?

[Beezil]

carpenter stole my photchop!

whata jerk!

:)

[ScottRoz]

Ed, you say that going larger is the "wrong way", but shouldn't a larger bore help, if the problem is the pedal going to the floor and not that you have to push hard on the pedal?

Scott

[Ed A. Stevens]

Originally posted by ScottRoz
Ed, you say that going larger is the "wrong way", but shouldn't a larger bore help, if the problem is the pedal going to the floor and not that you have to push hard on the pedal?

Scott

The two issues are separate symptons.

1. Pedal to the floor (Lack of adequate fluid volume in the pedal stroke):

Failed vacuum booster? (excessive pedal rod travel with minimal brake rod travel)

Air in the lines? (compressibility in the systems)

Poorly adjusted shoes? (demanding volume to snug the wheel cylinders).

Failing (balooned) brake lines? (new lines, braided steel lines)

Basic components in good condition are a great starting point, before swapping out pieces.

Calculate the fluid volume of two 1" bore wheel cylinders (four pistons, what I run in my D44) moving the shoes 1/16"? Not much. The disc caliper pistons move only a few thousandths (again, very little fluid volume). Compare this to the volume in the two master cylinder circuits.


2. Pedal effort (lack of stopping power):

Brake swept area? (fixed with the XJ other than 9x2.5 shoes, 10x1.75 shoes, and 10x2.5 shoes. There is a slight change in pad size between 84-90 front pads and the longer/thinner 91-02 pads. Maybe SJ truck 11x2.5 shoes and WJ knuckles/rotors/pads or rear discs?)

Pad material? (lots of options)

Poor pedal leverage ratio? (fixed in the XJ)

Poor vacuum assist ratio? (single or dual diaphragm XJ, small XJ or large SJ diameter, or hydroboost)

Poor hydraulic ratio in the master cylinder bore? (stock 1" compared to: 1 1/8" with less line pressure for foot*lb force, or 7/8" with more line pressure for foot*lb force).

Poor hydraulic ratio of the master cylinder bore to the caliper and wheel cylinder bores. (front calipers are fixed design XJ, maybe a WJ swap increases the caliper bore area, and larger rear wheel cylinder options have been explored from the factory 7/8" and 15/16" sizes).

Calculate the brake line pressure and compare percent increases (or decreases) at the end shoe or pad with each change. Changing parts, with no basis to achieve the goal in mind, may not net the result you want.

I know one common fear is running out of fluid volume in the MC. This is combined with many stories of poor pedal feel. I agree the factory pedal is not the best feeling brake, and the system has an affinity to retain moisture and trap air (possibly due to bubbling in the MC during offroad travel). The factory flex lines are also not immune from balooning (steel braid lines are an option). Repair and upgrades, and good maintenance, should counter these problems.

I run a single circuit 7/8" MC on one of my old drum brake cars, with 1 3/8" front (10x2.5) and 7/8' (10x1.75) rear wheel cylinders. The pedal effort is very good without a booster. The clearance volume consumed by the four wheel cylinders is much greater than that demanded by an XJ disc/drum system. If someone has a part number for the 7/8 XJ master cylinder, I'll be more than willing to test it out.

[REDXJ4FUN]

OK if your saying we neeed to go smaller we can try an AMC MC since they proble are all very clse in build and since they are cars they may have smaller bores. For instance an 84 eagle wagon has an 15/16 bore. but when i grew up on a farm i know that when we used a biger cylinder on the loader it lifted a heck of alot more justa little slower. but then again we don't need to move more fluid just more preasure so smaller would be better:confused1

[Ed A. Stevens]

Originally posted by REDXJ4FUN
OK if your saying we neeed to go smaller we can try an AMC MC since they proble are all very clse in build and since they are cars they may have smaller bores. For instance an 84 eagle wagon has an 15/16 bore.


You are not confused, the bore size has an impact of the leverage ratio on the application end (the master cylinder) and the receiver end (the wheel cylinders).

A smaller bore for the application piston provides more line pressure for the same effort from the mechanical device driving the piston (your leg).

A smaller bore on the receiver piston provides less effort on the mechanical device being driven by the line pressure (the brake pad or shoe).

Can anyone confirm the Eagle wagon master cylinder bore?

Are these disc/drum Eagles?

[vintagespeed]

Ok Ed, I've got a simple question. Having driven an E350, I have to say that those are some sweet brakes. The question for me is, what is the magic part of this equation? The booster? Why can't the E350 booster be made to fit the XJ?

[REDXJ4FUN]

Ok acording to the advanced auto web site the eagle is a 15/16 . Un fountunatly all of my amc books are stored away but may be Eagle might know of one that might be even smaller. and yes the eagle was disk/drum. i knoow at some point some one said something about a 78 firebird MC that worked but who knows.

[AJsArmor]

Just thought I'd throw my .02 into it. Before I swapped the 8.8 w/discs in I had completely gone through my braking system (rotors, drums, shoes, cyl...also new master). Was better but still just was pretty weak just running 33's. After I installed the 8.8, not a big improvement until I removed the o-ring in the prop valve. That was a the biggest improvement so far but still wasn't happy so I read about the E350 swap and that was by far a HUGE difference! Now it will lock up the fronts, not quite the rears which is perfect for me. Jeep doesn't do a huge nose dive under hard braking and to me is twice the braking performance than it was when it was stock with smaller tires.

Here's a rough pic showing the difference in bore diameter of the two, E350 is on the right.
http://www.ajsoffroadarmor.com/cgi-bin/upload/mastercylinder.jpg

[Ed A. Stevens]

Originally posted by vintagespeed
Ok Ed, I've got a simple question. Having driven an E350, I have to say that those are some sweet brakes. The question for me is, what is the magic part of this equation? The booster? Why can't the E350 booster be made to fit the XJ?


I understand the E350 booster can be made to fit with slight ovaling of the mounting holes. I have no doubt it can be made to fit. I question if it will provide the implied result, better braking force through greater brake line pressure?

What the larger MC diameter changes, is the volume of brake fluid pumped per unit length of stroke (more fluid per inch of stroke). The pedal is harder because the hydraulic leverage ratio decreases, it demands a heavier foot for the same force on the pads. It provides less line pressure in the brake system for the same foot pressure.

The observation that it works better (than the stock smaller bore MC) indicates the XJ brake system is not adjusted well, or has excessive slack volume (a drive rod that is too short, flex lines that balloon or piston/spring volume in wheel cylinders that consume fluid volume (pedal stroke), or the combo valve leaking fluid past the two circuits, or ?).

The E350 bore MC also works better with larger brake wheel cylinders and pistons on the wheels, the factory one-ton van application, because the leverage ratio is increased at the wheel end of the hydraulic line (1 1/8 wheel cylinders and larger diameter caliper pistons).

Any help?