Early brake booster options

[Fj40owen]

Have a 1970 FJ40 that we converted to a 77 front axle to get disc brakes.
Already have a wilwood master, but wanting to add a booster.
I am planning to get the bracket that allows the booster to clear the firewall rib, but my concern is the lack of space between the firewall and the carb/airbox. Would like to keep things neat and OEM looking so just curious if the BrainTrust has experience with booster/mc options that fit in this space.
thanks in advance.

 

[Mark Jennings]

Might look at Toyota T100 master cylinders. They are 1” bore and use a single reservoir for the front/rear circuits. However, they do not have the residual valve needed for the rear brakes….

I use this in my non-power 4W disc system, but use Willwood residuals in the front rear circuits and a proportioning valve to the rear.

I’m thinking in your case, deleting the front reservoir may give the clearance needed to the carburetor.

 

[Its me shaneus]

I have no answer but I am in the same boat exactly. Same disc front end and same master. Same firewall rib.

It works, but the pedal is pretty firm! This situation is about the best argument for a small block there is.

Hoping for ideas!

 

[Fj40owen]

I have no answer but I am in the same boat exactly. Same disc front end and same master. Same firewall rib.

It works, but the pedal is pretty firm!

Hoping for ideas!

Valid! thanks for following along.
Let me know if you get an answer somewhere else before I do.

BTW, since you are on the western slope you should join our group - 4cornerscruisers.com

 

[Its me shaneus]

Valid! thanks for following along.
Let me know if you get an answer somewhere else before I do.

BTW, since you are on the western slope you should join our group - 4cornerscruisers.com

Will keep an eye on your website and group. Local group (Bookcliff Cruisers) is no longer active as far as I can tell. Used to be in Four Corners (Farmington) a lot for work. Not as much anymore.

As for brakes, there are some electric systems out there as well as remote hydro boost. Both expensive, complex, and maybe hard to fit where you need. I gave up and wasnt willing to cut out rib so I just make do. Hoping for some new input!

 

[Skreddy]

My 1970 had a 4Runner booster or something and an unknown master on it when I got it with a spacer to clear the rib. Some PO had removed all the choke stuff from the carb to make that setup work and the carb was still really close to the master cylinder. They also moved the clutch slave over to make this work.
I went with a non-abs 80 series master with a spacer I made to adapt to the 3 bolt firewall pattern and run no booster. Moved the clutch slave back to stock location.
I am running mini-truck disc brake stuff on the drum axle and 78 rear drum parts (I think 78) because I think they bleed better/easier than the earlier design.
I do have increased pedal effort but I’m fine with it. A smaller bore will give you longer stroke but less effort. A larger bore will give you more effort but less pedal stroke. There’s a formula for figuring out optimum mc bore size but I can’t remember it or find it right off hand.
I’m running a sniper now but you can see in the pics how close it all was. The sniper is a little wider than the Aisin carb.

 

[65swb45]

Somewhere deep in the archives of the forum are pics of the firewall booster adapter that I have been selling for almost 30 years…in an engine compartment with a 1F carburetor.

www.marksoffroad.net

A 60 master cylinder would be even more compact.

I sell rebuilt factory boosters as well.

 

[Fj40owen]

Somewhere deep in the archives of the forum are pics of the firewall booster adapter that I have been selling for almost 30 years…in an engine compartment with a 1F carburetor.

www.marksoffroad.net

View attachment 3786944

So you are saying it fits.. it's just tight!
Have a top view by chance?
What booster/Mc is in this photo

 

[Skreddy]

Somewhere deep in the archives of the forum are pics of the firewall booster adapter that I have been selling for almost 30 years…in an engine compartment with a 1F carburetor.

www.marksoffroad.net

View attachment 3786944
A 60 master cylinder would be even more compact.

I sell rebuilt factory boosters as well.

Wanted to add, the spacer on mine I reference above was NOT one of Mark’s spacers.

 

[65swb45]

So you are saying it fits.. it's just tight!
Have a top view by chance?
What booster/Mc is in this photo

I put the yellow plug between the stock air cleaner and the MC to show just how close the two are. I took that pic sometime before 2011, as that is the date on the post that I lifted it from.

The booster and MC are both stock Landcruiser.

 

[Fj40owen]

I put the yellow plug between the stock air cleaner and the MC to show just how close the two are. I took that pic sometime before 2011, as that is the date on the post that I lifted it from.

The booster and MC are both stock Landcruiser.

Great info, thanks!

Let me know if you ever want some work done on your website. Maybe we can swap some work for parts.

 

[45Dougal]

Alternatively you can use a remote booster, which you can then place anywhere that you have space - probably on the inner fender. You can choose then to boost only the front, or use two single circuit boosters, or a single dual circuit booster, depending on your exact setup.
Very common on older and smaller British cars, and still used in some plant vehicles such as JCB.
This is how a dual remote booster (servo) looks.
There's even room on a VW T2.

 

[firemanj92]

So you are saying it fits.. it's just tight!
Have a top view by chance?
What booster/Mc is in this photo

I have 6/70 with a 60 series master (CityRacer) and OEM carb/airfilter housing and it fits with lots of room.

edit: no spacers used.

 

[Fj40owen]

I have 6/70 with a 60 series master and OEM carb/airfilter housing and it fits with lots of room.

edit: no spacers used.

Thanks!
Did you cut the firewall rib to fit the booster?
Would love to see a pic if you have one

 

[firemanj92]

No cut, different firewall (I realized late) but my firewall's rib doesn't extend up. My truck is an anomaly, although it's a 6/70 build it has a lot of 71+ stuff like the firewall, emissions, front seat, hazard switch. It was built in a transition month so it makes shopping for parts a little work. It's all original with 37k documented miles minus the front brakes/booster and little to none butchery done to it (barn yard find).

Pics posted above in edit

 

[Green Bean]

Don’t mean to hijack but curious as to when Toyota changed the configuration of the rib on the firewall. Our 40 has a manufacturing date of August 1970 and the firewall rib is configured to allow for a booster without a spacer.

 

[Its me shaneus]

Very interesting about rib change in 70 year models. Mines a March of 70 rig with the full height rib.

 

[Dave54000]

I have a early 70 as well and looking for ideas i saw this set up somewhere