How to test vacuum diaphragm for use on 68 FJ40 (1 Viewer)

[VA Mountain FJ40]

I thought I had a good diaphragm unit for my 68 FJ40 trans/tcase rebuild, but my test failed. I hooked my Mity Vac to each of the two hose inlets, and generated >20 in/hg vacuum, and … nothing. No movement of the shift fork, no movement on anything anywhere. I thought applying vacuum would make something inside move, but no.

Is my test method even valid?

Tried to look at the diaphragm inside the unit… and wrung off three of the six J bolts. I don’t see them for sale anywhere… so…

Who sells rebuilt vacuum 4WD activators for a 68 40 series? It would be nice to put a known good unit on my rebuild. Didn’t see anything in the classifieds.
Sure do appreciate the available help…
Chip
VA Mountain FJ40

 

[MDH33]

There's not much to them. If you can get it apart and clean/lube it, it will likely work. I bet you could find a good used unit that could be cleaned up in the classifieds. Lots get pulled when people upgrade the trans/transfer to 4 speed, etc.

I rebuilt my trans and transfer recently. I may have spare parts if you need anything. I think I have the j bolts too.

 

[charliemeyer007]

FJ40, FJ45 and FJ55 Vacuum Transfer Shift Assembly, 1958-9/71 Land Cruiser - Specter Off-Road

Toyota Land Cruiser parts since 1983. From the oldest FJ25 and to the newest Land Cruiser, Non USA or domestic 40 Series, 60 Series 80 Series or 100 Series, SOR has the largest selection of top quality new and used OEM and aftermarket Land Cruiser parts in stock in the world. Specializing in...

www.sor.com

I would take it apart and clean it so you can inspect the guts. I would only use real "red rubber grease" on those seals when you put it back together. GL I hate vacuum anything - that's why electricity and hydraulics' were invented.

 

[brian]

Mity vac should do it.

 

[middlecalf]

A clean hose and your suction should be enough to move the piston. Unit could be froze up due to corrosion/crud, or the diaphragm is split. You’ll have to dissect it to see what’s up on the inside.

 

[VA Mountain FJ40]

There's not much to them. If you can get it apart and clean/lube it, it will likely work. I bet you could find a good used unit that could be cleaned up in the classifieds. Lots get pulled when people upgrade the trans/transfer to 4 speed, etc.

I rebuilt my trans and transfer recently. I may have spare parts if you need anything. I think I have the j bolts too.

Thanks for the response! I especially appreciate the picture of the guts. It helps me understand what’s going on. This morning I got a hold of Georg at Valley Hybrids and he’s sending me a bench tested used vacuum pod. He says they are usually robust units but some do fail or freeze up over time. I still might rebuild my original unit but it’s worth getting a known good used unit to put in the truck and rebuild the spare after the truck’s back together.

Georg also said testing both ports with the Mity Vac should have moved the shift fork for at least 1, and with 20-30 inches of vacuum on the Mity gauge, that should do it. So my unit is likely frozen until it can be rebuilt.

 

[VA Mountain FJ40]

FJ40, FJ45 and FJ55 Vacuum Transfer Shift Assembly, 1958-9/71 Land Cruiser - Specter Off-Road

Toyota Land Cruiser parts since 1983. From the oldest FJ25 and to the newest Land Cruiser, Non USA or domestic 40 Series, 60 Series 80 Series or 100 Series, SOR has the largest selection of top quality new and used OEM and aftermarket Land Cruiser parts in stock in the world. Specializing in...

www.sor.com

I would take it apart and clean it so you can inspect the guts. I would only use real "red rubber grease" on those seals when you put it back together. GL I hate vacuum anything - that's why electricity and hydraulics' were invented.

Thanks for the response! After wringing off 3 of 6 J bolts, I’ve ordered a replacement used unit from Valley Hybrids to put in the truck. Sooner or later I’ll drill out the wrung bolts, see the situation, and either source rebuild parts… or put what’s left of the vac pod up on the Mud classifieds as is to help someone else out.

 

[VA Mountain FJ40]

Mity vac should do it.

Wow. THANKS for the video. Now I can see that I did hook the Mity Vac up in the correct way.
You showed me which vac tube moves the fork shaft out.
You helped me validate my unit isn’t doing like it should.
Even better news—found one.
Georg at Valley Hybrids is shipping me a bench tested used vacuum shifter unit today.

 

[VA Mountain FJ40]

A clean hose and your suction should be enough to move the piston. Unit could be froze up due to corrosion/crud, or the diaphragm is split. You’ll have to dissect it to see what’s up on the inside.

Thanks for taking the time to share this important information. Unit is def frozen for some reason. But I did find one!
Since Georg at Valley Hybrids is sending me a bench tested used unit, I can get the truck back together sooner and sort out what’s not right on the frozen unit at a later point in time.

Man, I sure do appreciate all the generous help and resources on Ih8mud.

 

[SteveH]

I thought I heard years ago that the FJ62 vacuum shifting diaphragm is the same size as the 1960s ones. Might be a path forward when all the used/old ones are gone.

 

[65swb45]

I sell used and refurbished units. I did one for @royal cake a year or so ago.

Seems like I am slowly slipping off of a lot of radar screens

 

[royal cake]

Mine is working perfectly - thanks Mark!

 

[Living in the Past]

I thought I heard years ago that the FJ62 vacuum shifting diaphragm is the same size as the 1960s ones. Might be a path forward when all the used/old ones are gone.

I am pretty sure the FJ62 diaphragm is larger. Could verify if needed.

 

[VA Mountain FJ40]

I thought I heard years ago that the FJ62 vacuum shifting diaphragm is the same size as the 1960s ones. Might be a path forward when all the used/old ones are gone.

Thanks for your response!

 

[VA Mountain FJ40]

I sell used and refurbished units. I did one for @royal cake a year or so ago.

Seems like I am slowly slipping off of a lot of radar screens

Thanks for the reply, Mark. I know you’re out there, and I’ll continue to check your Ruf Toys inventory for future needs as I go through the build. The engine I’m about to put in my 68 FJ40 has one of your E67 Vac Adv distributors with the Elec IGN conversion kit, and an updated coil. You set up the dizzy for me. Thanks for being a loyal vendor and knowledge contributor.

 

[VA Mountain FJ40]

Follow up…

I got a good used early vacuum pod from Georg at Valley Hybrids. He bench tested it before shipping.
Georg is a helluva good guy.

Georg’s used part works like it should, unlike the vacuum pod I had on hand. It arrived as it sat in used inventory, just needed some cleaning and a little paint.

I plan to install it on my freshly built Valley Hybrids transfer case later this evening. The degree of finish on the pod is almost as good as the fresh TC.

And yes, my original test method was valid. I was able to see the 4WD actuating fork in the vac pod slide back and forth by applying suction to the appropriate input vacuum tube. Didn’t need MityVac, mouth suction was enough on the good unit.

Again thank you for all of the helpful advice. I will post the final picture to this thread of the installed. Vacuum pod after the task is completed.

 

[middlecalf]

Fork looks in good shape too, common for it to have significant wear. But Georg wouldn’t send a worn one, he’s definitely a valuable asset for this community. Glad things don’t suck anymore .

 

[VA Mountain FJ40]

Hey… do I put anything on the gasket between the vac pod and the transfer case at installation, or just put it on dry?