12HT 1986 Vacumm pump/Alternator

[pepela]

Finally drove the cruiser about 10 meters today, hard brakes, brake light on and virtually no vacuum at small pipe, which I been crazily testing everything but the Vac pump because I thought it wasn't very old and probably done 10,000kms from new or recond replacement except that its sat for 2 yrs while body replaced / rebuilt. Is it possible the pump needs to be primed with oil after sitting so long or should I be considering replacing the internal or go through the knee bender and fork out another $400 ish to replace it. Is this common as it will be the second in 10 yrs both times being where the car was left to sit for long periods. Be cruel to be kind if ya have too please..

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[HJ61 12HT]

I would first try a little bit of oil in there and see if that helps, if that dosen't do much then pull it apart, its fairly simple, you may just need to clean stuck vanes...
It could also be the check valve that is in the outlet of the pump, its pretty easy to remove and test also.
The vanes should be about 40 X 14 X 6mm, I guess if there is an oil problem the vanes might have worn out...

 

[lostmarbles]

Hullo again Pepela.

If it is like my BJ40 (and I'm expecting it should be), it should have an oil supply line and a line that dumps the oil (together with the air it sucks from the booster) into the engine's crankcase.

It's certainly important to have this oil flow. They seem to last indefinitely if lubed correctly but rapidly wear out if run dry.

Of course your problem could be in the booster itself - but then you'd normally be able to hear the air being sucked in around the worn seal or whatever.

 

[pepela]

Thanks very much again fellas you both got very valid ideas that haven't been explored fully. When it comes to just listening makes it hard to say for sure and fan clutch noise tends to confuse me rather than be confident. This check valve I have to look into more carefully as I really hate the $2 item that causes a big issue and the more I have played with all these variables the more my confidence gets shot down but yeh it certainly could be sticky which agree won't last long before its well and truly buggered if that's the case. A mate had told me it was a common thing which pretty much happens when it's notting getting used or been protected for a long period which was originally planned half the time but kept wanting to do all the other things while it was under good shed cover. I try with all the suggestions and look up some more specs for what vac pressure or volume is suppose to flow what way get back to you later on how I go again I must say this becoming a very enlightening process on knowing the whys and what goes for the future outback trips I like to be prepared for.

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[lostmarbles]

I believe these specs are what our pumps should have (on Denso diesel-landcruiser alternators of the late 70s and the 80s):





PS. I haven't seen such detailed specs like this published in any Landcruiser FSM and I think I found this in the specs for a B-series engined Coaster or Dyna.

 

[pepela]

Thanks for those specs I just seen them after spending some time doing some checking and testing and Bugga me it turns out that I DID HAVE A BRAKE BOOSTER ISSUE which seemed ok and having no real test for it I just removed the vac feed pipe to it and shoved a bolt in it and started motor and vac brake warning light was off and ENGINE SHUT DOWN worked via the key again which it hadn't unless I picked up the revs. I happened to have a spare booster from the 84 I bought for my body swap which appeared to have been replaced at some time so I gave it a go and BUGGA ME BRAKES AGAIN SOFT PEDAL No warning light and Shut Down working, so it's looking real good to your first thoughts LOST MARBLES AND OWE YA BIG TIME. The amount of time I mucked around is totally EMBARRASSING but concede my inexperience with Vac Issues can have you looking in a million spots and just hope when I can get it out on the road that some other issues don't come up but at least I got a good insight thanks to all the blokes throwing in ideas which have helped too. Only 1 issue to look into from all this I noticed the TURBO green light didn't work but maybe my imagination or may have bumped something but imagine if that's an issue you be seeing it up here soonish lol

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[pepela]

Hullo again Pepela.

If it is like my BJ40 (and I'm expecting it should be), it should have an oil supply line and a line that dumps the oil (together with the air it sucks from the booster) into the engine's crankcase.

It's certainly important to have this oil flow. They seem to last indefinitely if lubed correctly but rapidly wear out if run dry.

Of course your problem could be in the booster itself - but then you'd normally be able to hear the air being sucked in around the worn seal or whatever.

This put me back to where I should have been looking had I done the right tests like I did the other day. I couldn't hear Vacuum loss but 12HT turbo and fan clutch noise concealed the booster noise that I convinced myself I thought I could hear but declined due to the other noises. Somehow after reading Lost Marbles comments I knew I was missing the obvious so I went back over it and was disgusted in myself. Really glad that you guys like to point out stuff I should have picked up and I revisited just to save me pulling the vac pump down too. BIG THANKS LOST MARBLES AND TO HJ61 which had me looking at check valves too!!!!!! HOORAY.CLAP

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[lostmarbles]

My morning ritual is to sit down at the computer and have a squizz at what's happening on ih8mud. And it always brightens my day to see someone such as yourself who's overcome a problem and is grateful for the advice received.

Glad you got it sorted Pepela.

 

[MalO]

I would first try a little bit of oil in there and see if that helps, if that dosen't do much then pull it apart, its fairly simple, you may just need to clean stuck vanes...
It could also be the check valve that is in the outlet of the pump, its pretty easy to remove and test also.
The vanes should be about 40 X 14 X 6mm, I guess if there is an oil problem the vanes might have worn out...

Hi Lost Marbles.. I have lost brakes!.
I was lucky enough to get a completely rebuilt 12HT, injector pump, the works. The Alt/Vac pump had about 100ks on it. After a few weeks of the brakes seemed crappy and after replacing back shoes I decided to fix the crap brakes and the persistent brake light. I assumed the brake light was low brake fluid not knowing about the vac switch to it.
So, it turned out that the Vuc pump was a dry as a dead dingo's donger. No oil coming up from the block, cracked the banjo bolt on the block with engine running, high oil pressure but no oil coming out. Got a mirror and torch to look in the hole but seemed to be blind ??/ WTF. I know only a tiny amount of oil is needed, and maybe there is a side feed into the block. Does anyone have an engine out so that they can have a good look? The block was acid dipped and christ knows what else, but would they have blocked that hole off for any reason?