XJninja

Ive got this funky brake set up in my my Jeep that is not working. There is no brake booster on my master cylinder and on the passenger side under the coolant overflow tank is an ABS Actuator/Pump that is malfunctioning. (Makes a buzzing noise for about a second every 15 seconds) ABS Light is on and my brakes are basically manual because this pump controls the power assist for the brakes. The part is around $500 or more and I am not planning on fixing it. Im thinking I can swap it out for a master cylinder with one that has a brake booster with no abs. Anyone know what I should be looking for and what exactly what I'll need from a donor jeep? Seems pretty straight forward... swap the master cylinder and maybe some brake lines... Am I overlooking anything??

DJKnightmare

Welcome to my world!

What you, we, have is called the Bendix 9 brake system. It was an option on the 1990 model only. Jeep realized that it was such a horrible piece of $h!t that after only one year they no longer had the option available. WHEN the system fails, you will continue to have non-power brakes.

I believe that you will also need a new brake proportioning valve. I have not done mine yet, but when I do I will do a write up, if you beat me to it, please post any issues you have aslo. Feel free to pm me with any questions. I will look around some more and find a write up.

The National Highway Traffic Safety Administration has put out a recall on your failing pump. So tell them to shove that $500 up their tail pipes. Where they get you though is that if your truck has over 100,000 miles then they say that they "HAVE" to replace the high pressure hose that runs from the pump back to the pressure ball....and that that hose costs them $800.00 and I heard that from 2 Stealerships. Must be made out of Titanium, gold and silver.

Administrationhttp://www-odi.nhtsa.dot.gov/complaints/results.cfm

TrekkerJmm

PM sent..I have a Brake booster and MC for sale from a 1992 xj...Tj

XJninja

Yeah, I found a recall on the part and had my gf talk to the stealership. They looked up my jeep by VIN and guess what the piece of sht pump was replaced and its fkd again! They told her good luck finding the pump or someone who knows how to work on it. LOL.. My immeadiate thought was why bother fixing it?I'll just update the whole system to a brake booster master cyl and be done with it.

Pressure Ball? WTF is that,lol. $800 for a hose? I could prob buy a whole brake system swap for less than $100. Am I going to blow the car up if I start disconnecting stuff? I noticed on the actuator it says danger! high pressure...

Where is the brake proportioning Valve? Prob gonna start looking at the yards for a good swap this weekend. You know what years dont have ABS?

DJKnightmare

https://www.cherokeeforum.com/member...ssure-ball.jpg

your pressure ball is the "same" as the brake booster. It stores the the pressure for your brakes. When you hit the pedal it uses this pressure until the pump catches up. I thought it was a mis-print until I saw it but that ball holds about 2,000 psi of pressurized nitrogen and brake fluid.

Here is a decent site about bendix 9 systems.
http://www.aa1car.com/library/abs_bendix9.htm

XJninja

I gotcha... Good lookin on the bendix 9 info!

Im going to clear the codes by "removing the ABS BAT fuse from the fuse panel for 10 seconds" as theyre saying on the Bendix 9 page... You wouldnt happen to know off hand which fuse that is would you. Im guessing one of the few big black ones under the hood pass side...?

Also got to check the fluid level and perform the correct bleeding procedure to be sure there is enough fluid. If that doesnt do anything I'll get a friend to scan the thing and see what comes up.

EVcherokee

I've got a 90 XJ with the horrible Bendix 9 too! I'm planning on intstalling a double diaphram vacuum booster from...I think '96 is the year. From what I understand the 96 year will fit the best and willn't raise your pedal as much. I got it priced out at Carquest and it will run about $200 for a remand master cyclinder and booster. I already picked up a porportioning valve at the jy. My biggest hang up is finding adapters to hook on to the stock lines. The ABS doesn't use a standard double flare,but something called a "bubble flare" I think in one of the links I have it mentions an adapter, but doesn't give details. Either that, or I'll pull full hard lines out of a jy XJ. I don't think it would be too hard, but I'm still weighing options.

Heres some links that might help:

https://www.cherokeeforum.com/f51/xj...-upgrade-3352/

https://www.cherokeeforum.com/f2/con...r-brakes-1631/

http://www.naxja.org/forum/showthread.php?t=924285

Keep us posted and please don't hesitate to take pictures and do a write up. If I do it before you, I'll be sure to write it up

-One more thing- Before tearing into the ABS system it can be depressurized by pumping the brake pedal something like 40 times with the ignition off. some of those hoses are under A LOT of pressure as mentioned above

EVcherokee

For some reason I didn't see your previous post...swear it wasn't there when I started writing..anyway, removing the ABS fuse will only disable the ABS computer and not the power assist portion of your brakes. The problem your having is that the power assist portion(your pump) on yours isn't working. The reason people remove the fuse is so the brake behave more like normal vacuum assist brakes(the computer willn't take over if you start to loose traction). This really helps on snow and ice, because if you know how to drive on snow and ice, ABS is your worsted enemy because you can't feel what the tires are doing. Since your pump is going out I'd just swap to the normal vacuum booster/master cylinder setup. If your running 33's or bigger, or you plan to, get the double diaphram booster I mentioned previously. I think I read somewhere with disc brakes in the back and a double diaphram booster, you can lockup 35's...thats braking power!

XJninja

Yeah pretty sure its beat... until I get the 4.5" lift and 33's i was trying to get the brakes a little more on the acceptable side if I can... Manual brakes are sht in any condition...lol. Im just gonna swap it out to the double diaphram & master cyl... wont be too much to tackle and should be cheap at the J.Y.

Lets_Ride_all

Do any of you guys that are converting your 90's over have the high pressure hose you are removing? I blew the hose and not really wanting to convert the system over yet. The dealer wants 295 dollars for the hose.

XJninja

yeah you have to replace it with the correct hose. Super High pressure will likely blow any other hose you try and use, but not totally sure... Maybe you could fab something up, I dont know... check the junk yards and ebay or.. fork over the cash and replace it with the right part..

Heres some relevant info on this system...

http://www.aa1car.com/library/abs_bendix9.htm

Lets_Ride_all

The JIC fitting is a 5/16 by 24 thread pitch. This is why people are having a hard time finding the fitting. It is not standard. My thought is to use a steel tube for break line (should be good for the 2000 PSI) and put a flange nut/end on the line that will screw onto the nipple.

fishtaconc

go to any hydraulic supplier they will have JIC, AN is the same thing 37° flare itll be a lot cheaper

EVcherokee

Does anyone know what size flares are on the hard lines that go to the brakes? To clarify, I'm talking about the end of the hardline at the porprtion valve. I heard they're a bubble flare, but I need the size so I can have the adapters all setup before I swap my brakes.

Lets_Ride_all

Found a house. It will be 41 US dollars delivered to the supplier. If anybody else needs one it takes about 3 days to get in.

Thanks everybody for the help you provided on this.