Master cyllinder upgrade

OK so the CJ brakes are non existant since the master cyllinder is toast. time for an upgrade instead of replacing a weak part again. Rob recommended a MC from a mid 80's Crown Victoria with hydroboost. From what i read it sounds like the way to go. I did read that it taps into the power from the power steering system? Is that right?

"The hydroboost system is also dependent on pressure from the power steering pump so if you stall the vehicle while crawling over rocks you will still have manual brakes but after a pump or two you will lose the hydroboost"

more info on hydroboost systems.

The Hydroboost System© works with 2 wheel & 4 wheel disc & requires a beefed up power steering pump. The complete kit including Hydroboost, Master Cylinder, Direct mount bracket (no fab work required), hoses, and brake lines. There's no drilling or cutting of your vehicle involved. Typically this kit takes about 2-3 hours to install, plus the time required for the power steering pump modifications if applicable.

94+ Jeep stock power steering units put out 1,100lbs of pressure. When you add this hydroboost you need a pump that puts out 1,500lbs to be able to use both the steering and the brake unit. If you have a pre-94 Jeep with power steering your stock pump should be ok. For 94+ models there are two routes to upgrade the stock power steering pump. The first option is an upgraded stock power steering pump that will work fine with the hydroboost and factory power steering. This is usually a direct bolt on upgrade that will deliver adequate power for the hydroboost, and the power steering system will continue to work as well as it did stock. Due to Jeep’s manufacturing tolerances there is actually a 1 in 2 chance your stock power steering pump will work fine, and a 1 in 4 chance it will work as well as an after market modified stock pump, so you may wish to try your stock pump before going this route.

If you are looking for a power steering upgrade at the same time, or if you run hydraulic assist steering, you will need a more powerful pump. For these applications look into the aftermarket high-performance power steering pumps.

SO my first question is can i use a hydroboost system after I later convert to full hydraulic steering(future stretch of the front axle forward about 6")

good question, I would half to say your going to have to figure out how much pressure your psc pump( or something like it) and how much pressure is required to push the ram then do the math. Personally anything that had to do with the brakes that required the motor to be running to fully work correctly, I would be a little Leary. Put it this way if your engine shuts down or a line blows you loose steering and brakes ,

Dont need the hydroboost just the master cylinder for that

I like the performance of the hydroboost from what i've read but i think i may just go the safe route and get a dodge 2500 master cyl and a booster from a 95YJ with the dual diaphram.

I think u have rear disk the master Cyl. from a 1979 mercury grand marquis with a deisel & hydro boost it will work fine with the vac. booster we use this on everything its almost direct fit

OK I understand now. So I don't want to convert to hydroboost I just want the master cyl from one. I definitely need to move more fluid with the 1 ton brakes. any rod adjustments required with the mercury or crown victoria? It's also been suggested that i try the 85 E350 van MC or the 2000 Dodge 2500 MC on Pirate. I'll be buying one of the 4 today so any addtional feedback would be greatly helpful.

going to go with the merc MC if the local NAPA has it. If not then the crown victoria. The E350 and dodge were originally for read drum setup best i can tell.

ok so the mercury and crown victoria MC have the same part number, duh. MC39467.

Either way you rely on the engine running for boost. You loose vac. to boost with after 1 or two hits with the engine not running also. Vac. system is probably the way to go. If a vac line brakes on the trail, it's fairly easy to rig that up. If a high pressure line for hydro fails, not so easy unless you have a spare, now no power brakes or steering. Kinda that putting all the eggs in 1 basket thing. the less liquid plumbing the better. I would also worry about the volume of flow as much as I would the pressure with the hydro-boost. I think the vac. boost is the way to go.

Yeah I agree. there was a misunderstanding though. It was recommended that i use the MC but not set up the hydroboost system. I wouldn't want to use the hydroboost because phase 2 will involve linking the front and rear and using full hydraulic steering. That would be too much for the pump to handle from what i've read.

Bill just change your master and you will be fine dont need other shit...

jealos-z wrote:

Bill just change your master and you will be fine dont need other shit...

Thats what I'm doing. I misunderstood at first. I need a rear proportion valve. Looking at wilwood now.

Tried to bench bleed the new master cyl and only the front chamber would bleed. I used the two plastic lines that come with the MC and fluid only came from the one compartment so i figured it was a pinched plastic line. Made my own bleeder out of some old line and fittins and same result. When bench bleeding you should get fluid from both correct?

ummm never mind. Just remembered that the lines going back into the MC have to be submerged. Bled it again and works just fine.