after swapping a chevy 4.3 into my 95 4runner, I had to lose the anti-lock rear brake pump that was bolted to the front passenger frame rail. I re-plumbed the rig like it had normal brakes---but the rear has just never had the grabbing power it should. I figured it was the proportioner valve, so I tied it up--then bypassed it altogether. now I have decent rear brakes, but it is hard to stop on big dropoffs. I have lots of experience wrenching and know the brakes are adjusted right. the master cylinder i only 2 years old, but I am starting to suspect the master cylinder itself was not designed to put out much pressure, and relied on the anti-lock pump to do the work. anyone had this problem and switched to another master cylinder? perhaps from and fzj80? any ideas? I took the proportioner valve out of my old '83 pickup years ago, and it spun me around in a circle the brakes locked up so hard....seems like my '95 should do the same
better brakes
- Thread starter black95
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my buddy had a 3rd gen 4runner with a dana 60 rear end and all that poop and he wasnt happy with the braking power untill he put a chevy master cylinder setup in.
i recall a disscussion about this a few years back.
seems a guy put a cruizer master in it... be worth a search. dont know if it was the zj80 or not...
i bet you could find out real quick on pirates faq
seems a guy put a cruizer master in it... be worth a search. dont know if it was the zj80 or not...
i bet you could find out real quick on pirates faq
The Marlin master cylinder has a 1" bore, so should the '95 4runner. You could use a t100 MC which has a 1 1/16" bore, but going to a larger bore will just make the pedal stiffer . . . is the pedal spongey right now? I'm not sure if your truck has the dual diaphragm brake booster already, but if the pedal is too stiff that might be an option
- Thread starter
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I'm thinking there's something different about the 4runner master cylinder because of those anti lock brakes I no longer use. maybe I'm crazy, but I know the system is plumbed right, and I have had two other toyotas that had fantastic brakes. doesn't make any sense that this 4runner is not locking the rears with no proportion valve at all, those drums should be much stronger than the disks up front. strange. not so much concerned about a BIGGER master cylinder, maybe just a DIFFERENT master cylinder??
Did this ever get sorted out?
Wilwood manual brake proportioning valve - the shiny fittings are SAE standard for 3/16" brake line, the only metric (Toyota) fittings are the rusted ones that I re-used on the master cylinder, the Toyota fittings worked perfectly with the 3/16" line and mixing them on the line made it easy to adapt
(note: all brake lines where bent with a tool, brake line doesn't bend very nicely by hand - it has a tendency to kink)
Took the LSPV off. The line that needs to get bent down to the flexible brake line is the one at the top of the LSPV - there is an -> next to the brake line on the LSPV. The line with an "F" next to it ties into the front brake line and can just be bent back or cut off . . . .
. . . . once you plug the front "T" I just took a fiting and put a big puddle of weld in the middle of it to make my own plug.
NorCalBorn
10 Year
15 Year
*Not to counter Corax's input, keep in mind that he has a 1st Gen Runner, with a different system initially that he has had to do a lot of work on to get it where he likes it.
The '95's I know where you are coming from, as it's what I have. Really consider the Chevy master if you have not done this part..
Hook up a hydro-line gauge and check your rear line pressure reading and overall bias. Mine was off by over 50% prior to anything I did as far as suspension and was only worse afterwards.
Also, the late '94's through July '95 (again mine) came factory with SWB13 calipers and 1 1/16" bore masters, if something has been swapped out in a repair i've found out that it was not a generally known spec and most parts places sell the 1" master by mistake, another thing I had to remedy on mine. (Although I am still mostly factory set-up my brakes now work like they should.)
The '95's I know where you are coming from, as it's what I have. Really consider the Chevy master if you have not done this part..
Hook up a hydro-line gauge and check your rear line pressure reading and overall bias. Mine was off by over 50% prior to anything I did as far as suspension and was only worse afterwards.
Also, the late '94's through July '95 (again mine) came factory with SWB13 calipers and 1 1/16" bore masters, if something has been swapped out in a repair i've found out that it was not a generally known spec and most parts places sell the 1" master by mistake, another thing I had to remedy on mine. (Although I am still mostly factory set-up my brakes now work like they should.)
When you say off by 50%, do you mean that the rear pressure was 50% of the front pressure?
Normally it should be less to significantly less, so I'm wondering what you were using for comparison.
Normally it should be less to significantly less, so I'm wondering what you were using for comparison.
NorCalBorn
10 Year
15 Year
Here... LSPV and Pressure Specs. I have also since seen 3 rigs that were out of the factory that were all showing similar numbers. Spec is 688-828psi. If you lift a rig those numbers go even lower, so as I have a 3.5" lift. *All the 3 rigs, and mine had not been adjusted out of the factory until we worked on them to get the correct pressure, and only mine had a lift, a minor 3.5" at that. Thus adding a lift reduces the pressure even more.
Now, also keep in mind the late '94-95's also come with a decleration sensor, so even if you remove the LSPV, there is still some feedback going to the ECU, which it might be possibly slowing down the engine prematurely still assuming your system is still antilock, causing your idle to drop, thus changing the vacuum pressure, that although will initially spike due to the lack of draw, will not maintain vacuum as it would normally...
Make sense at all? Let me know if more clarification is needed, as i said, both Corax and I have been going through brake chit the last 9 months.
NorCalBorn
10 Year
15 Year
Yep, but make sure if it's the first time pulling your bleeder valves, chase the threads as there will be some burring from the factory, then bleed them a bit first to push out any bits so you don't corrupt your seals or the tool.
or you'll be doing what I did last week repainting backing plates and redoing seals. 
or you'll be doing what I did last week repainting backing plates and redoing seals.
Thanks NCB!
My '84's LSPV now looks like this (except the bolts have been replaced):
I had long thought to keep the adjustability as I feel the idea is a good one. However my lightest loading could only *just* barely lock up the rears with the lever at it's highest possible position. So I opted to reduce the complexity a bit. At some point I may get around to RDB's and then I expect the LSPV to be more influential.
My '84's LSPV now looks like this (except the bolts have been replaced):
I had long thought to keep the adjustability as I feel the idea is a good one. However my lightest loading could only *just* barely lock up the rears with the lever at it's highest possible position. So I opted to reduce the complexity a bit. At some point I may get around to RDB's and then I expect the LSPV to be more influential.