Replacing 1974 Booster

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Oct 12, 2005
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My 1974 OEM booster failed a few years ago and have not had time to deal with it. I started rebuilding the 74 booster that had brake fluid leak into it. I tore it down, repainted, and reassembled it, but was unable to get some of the external gaskets to finish the job.

Finally getting back to this project. I just received my new booster, an aftermarket dual diaphragm booster for later FJ40s. I thought it would be helpful to post comparisons.

On the Left is a 1978 FJ40 Bendix booster (OEM?) made in Japan. In the middle is my made in China booster, SKP SKBB058 ($105 shipped from Rock Auto). On the right is my partially rebuild OEM booster. The only single diaphragm booster is the right one.

On the post-its, I listed following:

OD: Outside Diameter
VOR: Valve Operating Rod (distance measured from back of booster, to the end of the threaded rod)
BD: Booster Depth (distance from the back of master cylinder to the firewall. For the SKP booster, the first number is with the spacer, the second without. Spacer measures approximately 3/4")
* All dimensions are taken as best I could, without a caliper (which I do not have).

Does anyone know offhand if the new SKP booster can be installed without the 3/4" spacer?

BTW, the Part Number for the 74, single diaphragm booster is SKBB059. The images you see on the internet are NOT accurate and actually reversed. They show the dual booster pictures for single booster and vise versa.

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It's all about clearance and length of rods. I think the 3/4" spacer was included to avoid contact with a rib on the firewall on some vehicles. The length of the rod connecting to the pedal needs to be the right length. I think some people have had to run a dies down the rod to get the clevis down far enough. Don't forget to adjust the rod that goes into the brake master as well.
 
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I'm not sure if this will be of any help: I recently replaced the booster and master in our 1970 with a new disc/disc set up. I tried it with the spacer and had a problem getting the brake peddle to line up. I then removed the spacer and everything seems to line up and work as it should. The brake lights required no adjustment.
 
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I'm not sure if this will be of any help: I recently replaced the booster and master in our 1970 with a new disc/disc set up. I tried it with the spacer and had a problem getting the brake peddle to line up. I then removed the spacer and everything seems to line up and work as it should. The brake lights required no adjustment.


Curious of your build date. 7/70 is when the first booster was used on an FJ40 in the US. This is also the date the brake lines increased in size and had a separate circuits front and back. These were considered to be 71 models.
 
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@Green Bean, What MC did you install?

Removing the spacer would give me extra room in the engine compartment, but the length of the rod would be too long. I would have to see if it would give me enough adjustment on the pedal side. I have not yet had time test fit it all.
 
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I sourced the MC, booster and proportioning valve from Red Line Cruisers. I believe the booster is from a 71-74; the MC is 1" non abs disc/disc. The Proportioning Valve is Wilwood. Justin @RLMS was a big help.
 
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Did you connect your MC to the truck brake lights? if so, where did you get the connector?
 
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At one time was collecting parts to update my 9/67 68 model to disc brake up front. I even removed a rib from a later cruiser to allow the booster to mount flush on the firewall. Just kept finding more that needed to be done. Think finding out changing the pedal was not a simple bolt in gave the idea up. Do believe the early firewall for a brake booster has a two piece rib.
 

1911

chupacabra
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Did you connect your MC to the truck brake lights? if so, where did you get the connector?
Yes. I found the appropriate connector on Ebay and was able to wire it to the brake light without too much difficulty. Here is my write-up:
 
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Yes. I found the appropriate connector on Ebay and was able to wire it to the brake light without too much difficulty. Here is my write-up:
Do you have the PN for that connector?
 

Spike Strip

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Just an FYI, if you use the Aisin/Advics BMT051 it's the same 1" MC except the fluid level sensor is in the reservoir cap so it's way easier to connect (splice) to your existing wires without having to source the connector.

This is from my FJ60 4Runner brake swap

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I have a MC from a 1993 pickup that I want to use. It looks similar, and may be the same as your MC (80 series ?) you used.
 

iptman

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When I installed an 80 series booster and master I’d have liked to have a spacer but couldn’t find a Vin of a Toyota pickup that came with one… and the dealer didn’t have a way to look one up without it (or so they claimed).

I did make it work anyway. It is way more powerful than a 40 booster, and the master is much shorter.
 
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City Racer sells the spacers. The SKP booster comes with a spacer.

Isn't China the new Japan?
 

1911

chupacabra
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Do you know that it's not made in China?

No; guess I should have said, skip the SKP unit and buy from City Racer.
 

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