Brake MC swap and rear conversion (1 Viewer)

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My 78 FJ40 brake pressure swithces are leaking out of the very bottom, not where they connect to the MC. I am getting so frustrated with this I could spit not to mention the constant adjustment to the rear drums. Seriously looking at converting to rear disk brakes but also want to replace the MC with something that will bolt in and not need a proportioning valve. I have heard a Mini or 4runner MC could work What year what Part Number?

Any suggestions to fix the pressure swithces as I collect the parts for the conversion?

POSER Do you have any rear disk brackets?
 
tcarlson78 said:
My 78 FJ40 brake pressure swithces are leaking out of the very bottom, not where they connect to the MC. I am getting so frustrated with this I could spit not to mention the constant adjustment to the rear drums. Seriously looking at converting to rear disk brakes but also want to replace the MC with something that will bolt in and not need a proportioning valve. I have heard a Mini or 4runner MC could work What year what Part Number?

Any suggestions to fix the pressure swithces as I collect the parts for the conversion?

POSER Do you have any rear disk brackets?


I can't help you with the pressure switches, but I have tried a couple of MC's.
If your going to run 4 wheel disc's, I would get a MC from a 4-wheel disc rig. I used
a fzj80. It works great, but your still going to need that proportioning valve for any MC if your going to use the montecarlo calipers.


aw
 
Installing a proportioning valve in the rear brake line (assuming you have a dual cylinder master) really isn't all that difficult (we found fittings without having to cut or flare lines, PM me for info on parts numbers). You want the front disks to brake before the rear and it should be easy enough to test that out on a dirt road (asphalt will wear your tires) with someone watching as you brake from around 15mph full stop. You then adust the valve accordingly. We just did the rear disks conversion over Christmas.
 
i have th fzj80 master on my 4wheel disc conversion and no proportioning vavle and have no problems braking in snow or ice etc. do a search lots of coverage on this subject!!
 
I have the rear conversion kit from TSM with no proportioning valve. They told me over the phone that at least 50% of the FJ40 conversions they sell end up not needing the valve.

In daily driving I've not had any issues, and only had one "panic stop" situation. In a hard rain some kids on bikes ran a stop sign right in front of me. The rears definitely locked before the fronts, but even with that the skid was nice and straight, and I was easily able to let up a bit, keep control and not kill anybody. (running 33X12.50 BFG MT's, probably about 75% worn for reference, in my experience not the best rain set up)

So, IMO, for daily driving you're probably OK without the proportioning valve, but I will probably put one in this summer anyway, just to be on the safe side.
 
Go here and read all you want to know about it
 
I did the TSM conversion and highly recommend it. Ran without the valve for a while and it was ok: since I had heard I needed it, I ordered and installed on. Only took a little fine tuning and the braking was better in a hard or panic stop.
 
This may sound stupid but here goes... :doh:

I have a 71 FJ55 with mini-disc. Ive replaced all my lines and adjusted the rear drums with the truck on jack stands. When I hit the brakes really hard, the front will lock and it doesnt feel like the back is working at all. I jacked the truck back up and with the brakes applied, I can get the rear wheels to turn under alot of force.

Would this be a master cyl or rear brake issue?

I have the MC setup out of a 92 mini to swap if that would help. Any suggestions or thoughts?

Chuck
 
Yotahilux said:
This may sound stupid but here goes... :doh:

I have a 71 FJ55 with mini-disc. Ive replaced all my lines and adjusted the rear drums with the truck on jack stands. When I hit the brakes really hard, the front will lock and it doesnt feel like the back is working at all. I jacked the truck back up and with the brakes applied, I can get the rear wheels to turn under alot of force.

Would this be a master cyl or rear brake issue?

I have the MC setup out of a 92 mini to swap if that would help. Any suggestions or thoughts?

Chuck

I would think that 1, you need more adjusting on the rear shoes, or you still have air in your lines.
Bleeed the rear again, and then adjust your brake shoes untill they just rub.Now go step on the brakes to center everything, and adjust them again.
Good luck

aw
 
Last edited:
Bad master or your residual valve is toast..
 
JTO sells a master cylinder that fits your needs. I have one with my rear disc set up and I have not needed a proportioning valve.
 
petescoffee said:
JTO sells a master cylinder that fits your needs. I have one with my rear disc set up and I have not needed a proportioning valve.
Most people need the valve, JTO sells the same master that MAF, SOR, Marlin and All pro sell.

It is nothing special..

I got mine for $80 from a local parts store (new, not rebuilt)
 

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