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-   -   Power booster upgrade? (http://www.jeepforum.com/forum/f8/power-booster-upgrade-1547495/)

bangarang 07-10-2013 07:08 PM

Power booster upgrade?
 
I want to buy a power booster for my '81 scrambler. Can I just buy the booster and put my original master cylinder on it or should I just buy the booster and mc together? Sorry for the dumb question.

brownbagg 07-10-2013 07:26 PM

thats what i did.

j33pman 07-11-2013 07:58 AM

the non-power brake master cylinder will not work with the power brake booster, you will need to buy a master cylinder as well

texas1al 07-11-2013 08:21 AM

If you're converting to power brakes, you will need the booster, new MC designed for power brakes, the bracket that sits between the firewall and booster, and new lines from the MC to the proportioning valve. If you're running the stock air cleaner that came with manual brakes, you will also need to either get the offset factory air cleaner that came on power brake equipped trucks or an open element air cleaner to give you the clearance for the booster/bracket.

2girlsAndaGuy 07-11-2013 12:04 PM

1 Attachment(s)
why do you say that he will need new lines from the MC to the prop valve texas? Just installed a booster on my rig, originally equipped with manual brakes and the lines screwed right into the new MC after stretching them out a bit.

Attachment 645182

j33pman 07-11-2013 12:07 PM

I changed mine over to power brakes a few years ago and I don't recall changing the brake lines.

Is that a YJ dual-diaphragm on yours?

2girlsAndaGuy 07-11-2013 12:25 PM

no it was a POL kit, came with the bracket and everything. Maybe the YJ booster used different fittings on the MC?

texas1al 07-11-2013 12:38 PM

I don't know if the originals will fit on the factory PB MC. I'm sure you could make it work though with fitting adapters or new flares and fittings altogether. It would probably save a bunch of headaches trying to unfreeze the fittings at the prop valve. Just be careful, from what I've heard, you've got a 50/50 chance of cracking the old steel lines when trying to straighten out the tight coils in the originals. I opted for a new set of pre-bent lines from the MC to the prop valve from inline tube since my originals were pretty ratty and the new lines fit great and look very clean tucked up to the original line bracket on the firewall.

Spieg8 07-11-2013 04:58 PM

Quote:

Originally Posted by 2girlsAndaGuy (Post 15666142)
why do you say that he will need new lines from the MC to the prop valve texas? Just installed a booster on my rig, originally equipped with manual brakes and the lines screwed right into the new MC after stretching them out a bit.

The master cylinder and power booster you installed is not a factory style setup (your master cylinder does not appear to be a Jeep model... maybe from a corvette? disc/disc?). Your experience may not pertain to the OP's question (seems like the question was about a more "factory" power brake upgrade (probably disc/drum), not a cross brand conversion).

Not sure if the stock manual lines will fit or not (doesn't hurt to try them first... if they don't fit, then buy new). Will definitely want a new MC designed for power brakes, a mounting bracket for the firewall, and the correct linkage to connect to brake pedal. I would suggest going with a dual diaphragm power booster (better performance/less pedal pressure), although that can compound the clearance problem with the air cleaner housing. Will also need to tap into engine vacuum for the power booster.

Spieg8 07-11-2013 05:11 PM

Quote:

Originally Posted by texas1al (Post 15666267)
It would probably save a bunch of headaches trying to unfreeze the fittings at the prop valve.

Agreed. Those old fitting are a PITA to get loose without stripping out the hex head. Use lots of PB Blaster, and maybe a little heat too. A tool I've found to be invaluable for removing old brake line fittings is the Vise-Grip 4LW locking wrench http://www.irwin.com/tools/locking-t...cking-wrenches. These things rarely damage the lines or fittings, and are small enough to get into most tight spaces. Much better than a conventional line wrench (line wrenches work fine for larger fittings but small brake line fittings are too easy to strip).

texas1al 07-11-2013 05:18 PM

Yeah, those fittings at the PV are a real pain. If you decide to go with new lines anyway, best bet is to cut the lines 1/2inch above the fittings and try to get a thin wall socket over top of them. Then actually try to tighten them a little to break them free. Heat is another good option, but be careful - I cooked my PV by mistake and ended up with fluid seeping through the rubber eyelet/seal right ahead of where the rear lines connect. Probably needed a new PV anyway, but that sealed the deal.


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