Do-it-yourself booster overhaul

[Racer65]

@lostmarbles,

Digging up this old thread to ask you a question (Anyone else who knows please also weigh in).

I recently sold a brake booster to a customer in Australia. He told me he has a 11/'74 FJ40, and he couldn't fit the booster due to a rib in the firewall. He showed me a couple of shots, but I can't see the firewall (he'll send more photos later). He says he has a single reservoir master cylinder with 3 mounting bolts, but he'll convert to a dual reservoir MC. The existing MC has 3 mounting bolts instead of 4, and therefore the holes in the firewall don't match up to the booster, which as 4 studs. I asked him how did his original booster fit. he says the original is a "remote booster".

None of this is making any sense to me. My question is, have you ever seen a FJ40 built as described above in your part of the world? My hypothesis is that he has a much older truck than he thinks. I believe he has a 60's era model (therefore the rib) without a booster, and at some point a PO added some type of hydro-boost.

I don't really want to get into showing him how to modify his truck, since that's not my expertise, but just for the sake of discussion, can he simply cut the rib and drill holes to mount the booster? Personally I've not seen it done this way before. What I have seen are people adding a thick adapter to hang the brake booster away from the firewall, or do a Man-a-fre Tandem MC conversion without a brake booster.

 

[antFJ]

it looks like a non-boosted master cylinder was mounted there. Overseas markets had brake drums all around and other stuff from USA 1960's era landcruisers in them for a while while the american market got upgrades.

that is probably confusing but.... here

https://forum.ih8mud.com/threads/brake-booster-master-on-early-40.713097/

In short the guy is confused. He didn't have a "remote booster" stock. He had a 3 bolt master cylinder. There are spacers available or he can cut the rib. His stock master cylinder will not work with your booster.

 

[antFJ]

jimC supplies a solution in this thread

https://forum.ih8mud.com/threads/19...version-issue-booster-hits-carberator.579830/

 

[pbgbottle]

The firewall is different on the older rigs. There is an adapter spacer available to fit the booster. it spaces the booster out away from the firewall. U will have to search here on mud for more info I can't search it up well on my phone.

 

[JohnnyC]

@antFJ

Toyota did have remote boosters (edit... made a new pic ... see pic below from a 55)

i posted pic of the booster from a manual before... but... cant find it now

For the single line masters... here is a pic of a 65' with an external booster ... leyland makes them... we used to put them on Brit stuff all the time... bendix also had a version as well as others

groovy offenhouser dual carby setup

 

[Racer65]

>>Toyota did have remote boosters

You mean it came out of the factory that way on some FJ40s?

In your photo, where is the remote booster? Is it the unit in the corner that looks like a compressor? How does it work?

The other thing that's odd is that, when comparing photos, I see the '65 has a very elongated rib down the center. The rib from my customer's truck appears to only come up half way.

 

[Racer65]

The firewall is different on the older rigs. There is an adapter spacer available to fit the booster. it spaces the booster out away from the firewall. U will have to search here on mud for more info I can't search it up well on my phone.

I've seen that solution. However, I'm wondering how can any booster have a pedal rod that long? That whole pedal geometry must be weird.

 

[Racer65]

johnnyC, I am blown away by that remote booster.

Australia was getting a '65 setup as late as 11/'74?

 

[antFJ]

wellllll heck i'll take a 50% correct answer

 

[JohnnyC]

I would need to look into the specifics for the Aussie market ... But... Many markets did get no boosters... I wod imagine that any could be upgraded to an external brake servo

 

[Racer65]

Got some new pictures of the customer's firewall. It doesn't actually have a center rib! I think he's talking about the channel on the left side that is expected to be there. I don't think he has any problem! Just need to drill 4 mounting holes for the booster to fit.

 

[Racer65]

Comparing with @lostmarbles ' firewall, I think the center hole needs to be moved up and further to the right. I don't know how that changes the pedal geometry. Therefore, it's not that straightforward.

 

[ginmtb]

Will it not clear the channel using the existing hole?

 

[Racer65]

I think he must've tried it.

 

[ginmtb]

Well moving it is a pretty straightforward - get a steel plate slightly larger than the four bolt holes. Drill out and cut the larger booster hole. Round edges of plate. Paint both sides matching colors. Cut hole in firewall to accommodate relocated booster. Seal plate and bolt up should be good to go.

Now the pedal geometry is a different story...

 

[JohnnyC]

I think he is going to be looking for one of the spacers so the booster can get past the rib ... If it is drilled it does look like it may interfere with the clutch as that's over too much as well... Let alone as the booster will not be inline with the pedal

 

[lostmarbles]

@lostmarbles,
Digging up this old thread to ask you a question (Anyone else who knows please also weigh in).
I recently sold a brake booster to a customer in Australia. He told me he has a 11/'74 FJ40, and he couldn't fit the booster due to a rib in the firewall. He showed me a couple of shots, but I can't see the firewall (he'll send more photos later). He says he has a single reservoir master cylinder with 3 mounting bolts, but he'll convert to a dual reservoir MC. The existing MC has 3 mounting bolts instead of 4, and therefore the holes in the firewall don't match up to the booster, which as 4 studs. I asked him how did his original booster fit. he says the original is a "remote booster".
None of this is making any sense to me. My question is, have you ever seen a FJ40 built as described above in your part of the world? My hypothesis is that he has a much older truck than he thinks. I believe he has a 60's era model (therefore the rib) without a booster, and at some point a PO added some type of hydro-boost.
I don't really want to get into showing him how to modify his truck, since that's not my expertise, but just for the sake of discussion, can he simply cut the rib and drill holes to mount the booster? Personally I've not seen it done this way before. What I have seen are people adding a thick adapter to hang the brake booster away from the firewall, or do a Man-a-fre Tandem MC conversion without a brake booster.

it looks like a non-boosted master cylinder was mounted there. Overseas markets had brake drums all around and other stuff from USA 1960's era landcruisers in them for a while while the american market got upgrades.
that is probably confusing but.... here
https://forum.ih8mud.com/threads/brake-booster-master-on-early-40.713097/
In short the guy is confused. He didn't have a "remote booster" stock. He had a 3 bolt master cylinder. There are spacers available or he can cut the rib. His stock master cylinder will not work with your booster.

I would need to look into the specifics for the Aussie market ... But... Many markets did get no boosters... I wod imagine that any could be upgraded to an external brake servo

Heck. You sure do go the extra mile for your customers Racer

I can confirm using illustrations from a Jan 1975 parts catalog that AntFJ and JohnnyC are correct in that this Aussi FJ40 came with that 3-bolt master and no booster at all in late 74:

So his remote booster must have been non-factory and added later.

Got some new pictures of the customer's firewall. It doesn't actually have a center rib! I think he's talking about the channel on the left side that is expected to be there. I don't think he has any problem! Just need to drill 4 mounting holes for the booster to fit.

I'm guessing he may need to modify his "pedal box assy" inside the cab to mount his new "dual circuit master complete with booster" higher - but I'd think it should be do-able to get something like what I have as shown here:

The above shots show the original AISIN master and this one here shows a PBR aftermarket master:

 

[antFJ]

Can your customer get a picture or two of his pedal assembly. I wouldn't be surprised if all he needs is a different pedal or no change at all. Toyota typically made their parts interchangeable... a rhd pedal assembly might be the same for a boosted and non boosted master in 1974

 

[Racer65]

Can your customer get a picture or two of his pedal assembly. I wouldn't be surprised if all he needs is a different pedal or no change at all. Toyota typically made their parts interchangeable... a rhd pedal assembly might be the same for a boosted and non boosted master in 1974

No, if he carves a new center hole, the pedal assembly must be changed. If he uses the existing hole, the booster will hit the rib on the left.

He's looking into using the JT Outfitter's adapter that pushes the booster out, but looking at @lostmarble's photo above, I think it'll hit the air cleaner. Also, the booster rod on the pedal side will need to be lengthened, since the booster sticks out over 3 inches.

 

[lostmarbles]

No, if he carves a new center hole, the pedal assembly must be changed. If he uses the existing hole, the booster will hit the rib on the left.

He's looking into using the JT Outfitter's adapter that pushes the booster out, but looking at @lostmarble's photo above, I think it'll hit the air cleaner. Also, the booster rod on the pedal side will need to be lengthened, since the booster sticks out over 3 inches.

I doubt his air cleaner will be where mine is (for my diesel engine)

But looking back at these pics from the beginning, I don't think raising the position of the booster is going to be the solution (regardless of any pedal-box problems associated with it). The diameter of the booster still looks too big:

(The booster would be rotated 90 degrees clockwise when installed of course.)

So spacing the booster away from the firewall seems like the best solution all round, even though it is going to "grab-the-eye" of anyone looking in the engine bay.

(Perhaps he could consider going dual-circuit without any booster at all? There's no reason why the pedal pressure should be higher than for this vehicle in its ex-factory state provided the bore of the master isn't increased?)