I bought a vacuum booster and a master cylinder of a wrangler on ebay and will be installing it on my 86 cj7 this weekend. my jeep has front disks and back drum brakes with a proportioning valve mounted to the frame. I noticed that the wrangler master cylinder has the brake lines coming out of the opposite side is this a problem? can I unbolt the wrangler master cylinder and bolt my CJ master cylinder on and not have to bleed the brakes? or do I have to use the master cylinder and booster as a set? where should I hook up the vacuum line to? anything else anyone can think of that I should do or should'nt do? thanks carmine
Have you made reservations for your funeral on Tuesday?
I think you might be in for some trouble making it fit, and the brake lines are sending you an important message.
Looking quickly in a mail order catalogue, I notice that the parts numbers for the 78-86 power master cylinder are not the same as the master for the 87-89 YJ, the 90-94 (without ABS) or the 95 YJ (with or w/o ABS). All different, as are the proportioning valves for 82-86 and 87-93. Even if you can physically make it fit (remember the sheet metal redesign at the end of the CJ run -- did they change pedal assemblies too?), you still should want to know if they are hydraulically equal. Looking again, the front calipers fit 82 through 89, then change for 90 through 00, the rear cylinders fit 76 through 89.
Call me a yellow-livered milktoast mamma's boy chicken corporate ass-sucker if you like, but I wouldn't mess around with brakes unless I knew for sure I was doing the right thing. The "right thing" in this case would be getting the right master and booster for my Jeep instead of trying to cobble something up from bits and pieces. You're not going to feel too good about it if the first time you panic-stab the brakes you lock the front wheels, skid and kill someone other than yourself.
Can you install a booster without changing the master?
In response to Lee's post, I have changed my Jeepster from non-power 11 inch drums to a Bronco Master and early series power conversion kit, Scout Booster, CJ disk front, and have significantly increased the brake effectivness and safety of my machine. I am certified as a Master Auto tech, so I do have an advantage here.
No, the master is totally different for power brakes.
There also are two varieties on top of that, one is for front disks, the other is for drum fronts.
A 'proper' power brake master for a CJ7 isn't expensive at all. He will also need the proper proportioning or combination valve for it.
On that note, I have had the chance to compare an 85 with manual brakes and my 86 with power brakes and the 85 stops a bunch faster than my 86. The owner of the 85 decided not to bother going to power after he saw the lack of improvement or an actual downgrade in performance.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
no Lee I have not made funeral arraignments. but I do live on the top of a hill from a school and when I work on my jeep I like to drink allot of beer and oh yea my emergency brake cables are rusted and don't work, you know those old jeeps. and my jeep has a supercharger 454 in it so I always have the throttle wide open so I don't use brakes that much. but I hope everything will be o.k. but seriously I called the guy who sold me the booster and he said it is off of a 94 wrangler with a 4 liter 6 cyl. I would think that if I keep the same master cylinder and proportioning valve that the front to back difference in pressure would stay the same and I would be increasing the pressure with the booster. just because they changed the part don't mean it wont work maybe they were just looking for a different pedal pressure. has anyone done a CJ to wrangler brake conversion? thanks carmine
You knew what you were doing. I don't have the same confidence "Jet". He bought the wrong part -- because he doesn't know what he is doing.
He bought it on E-Bay to save a few dollars, discovers that it doesn't fit, asks here if he can make it fit and when he is told "don't do it", runs off to another jeep group to see if someone there will say "sure, shoehorn it in and don't bother using bolts, just put some bailing wire on it instead. And use fuel hose to bridge any gaps in the lines."
Just because some seller on E-Bay says the part will fit doesn't make it so.
I'll tell you what his post reminds me of: About 15 years ago a local guy decided that he wanted a snazzier steering wheel but he couldn't be bothered to get the right one. The one he bought _almost_ fit, with a few spare parts left over and a bit of mickeymousing. He loaded up the car with three of his buds and went out of a spin.
At 50 MPH the snazzy new steering wheel decided that it really didn't like being mated to the steering shaft and refused to have anything more to do with it, the steering box or the rest of the car. He hit a nurse I was scheduled to work with that night head on, and killed her outright. She left a husband and two little kids, the driver got a couple of scratches and walked away.
"Jet" should resell the damned thing on E-bay and buy the right part for his jeep. He'll save time and money spent trying to make it fit.
lee I went to another group to get some other opinions and maybe find someone who has done this first hand. after I get a bunch of opinions I will make a decision whether i want to put it on my jeep or not. but that does not mean i am going to use bailing wire and a bunch of rediculous parts to put it on. almost all the wrangler boosters on ebay say that they will work on cj's. i may just put it back on ebay but i want to get as many opinions as possible.
Brakes are a device on which I never try to save money. I buy the best parts I can. When I hone out a bore, it gets larger, and to remove the corrosion pitting requires a lot of metal removal. I buy new hydraulics rather than rebuilt which are honed out to 'who knows what' size. In the case of rare antiques, i have them bored and sleeved in brass or SS to the original diameter. I have found that brakes shoes and pads of the cheap variety generally give more braking force than 'lifetime guaranteed" shoes and pads which are too hard. Mercedes and Volvo did it right, they used pads that will wear out, and soft nodular iron rotors, and you get powerful brakes with disposable parts. I can still buy Merc. 300 series rotors for $10 each, new and sell them for $20. I never turn rotors on either make. Volvo brakes always make noise unless you use factory pads, and Merc usually too.
I have seen 3 bad out of the box masters recently. The company selling them then changed brands. The different brand seems to be better.
Still a rebuilt in a box with a warranty is sure as shit better than a used of unknown wear one that needs to be 'jury rigged' to 'work'.
The pads I have in now are the long life ones and the grabbing power difference is noticeable big time because I am turning 33's. My friend with manual brakes and cheap shoes can stop way faster than me!
On my next change I am going back to the cheap ones for sure. I can return the long warranty ones and the store will give me a credit and the new cheap pads free. Nice outfit. I just did that with some expensive Heavy Duty 'lifetime' u-joints, got 2 cheap ones with grease fittings and a credit towards my next purchase.
It might work just fine, I don't know 100% for sure either way.
I just know that the master is designed to put out a certain volume of fluid at a certain pressure to match the volume in the sump behind the caliper and rear cylinders.
If it is too low, then the brakes might not grab as hard which can mean a longer stopping distance. The pistons in the caliper can be different sizes which makes the volume of fluid needed from the master a lot different to get the same end pressure.
When I see all the sellers saying the same thing almost exactly that they 'can' be made to work on a CJ7, that sets off alarm bells in my head.
Sorry, but I tend to try and be honest with my opinions and err on the cautious side and have them right more times than not. I can easily be wrong too.
If the booster is the same, then just putting a proper master and combination valve for a CJ on it should be really easy. I have no issues with something like that. It is the different masters and combo valves I have issue with.
Oh, just below your carb on the drivers side should be a large brass plug. This comes out and the brake booster line threads in there.
here is the email I got back from one of the many sellers on ebay that i emailed that are selling wrangler boosters on ebay
hi carmine, not sure who you are talking to, but they have no idea what they are telling you. I have since 1987 sold well over 800 boosters not to mention installing well over 200 unto customers cj model jeeps. it will fit, and will work well.
Yup. Like 95% of diagnostic problems, I cant tell if it will fit, work, or what's wrong, unless i can see it, hear it, and do my own tests. No advice is often better than bad advice.
On 07 Dec 2003 12:07 PM, Jet posted the following:
What I don't get is why you are willing to take the seller at his word when he has a financial incentive for saying what he does, while you insist on disregarding the advice of the people here who know Jeeps and have nothing to gain by misleading you.
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