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I have a 92 patrol with the vac pump on the back of the alt. I want to convert it over to the vac pump system that the later TD42's use with the pump off the alternator.

how do they get their vacume and can you post some pics of the setup if you can. Also could this be done to my 92 engine and what would be involved in doing it?
 

· naturally asthmatic
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I can't help you much with the drive belt pump but you could also consider an electric vacuum pump. I presume Old Mav's mount for "on board air" would work to add a pully vacuum pump. I think that he said this was the location of the vacuum pump on the GUs.
 

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They are gear driven off the timing gear's, I imagine it would be lot's of stuffing around, prob need the whole front timing case???

I assume like me you want a high output alt but are having troubble getting one due to the vac pump???
 

· naturally asthmatic
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Check the onboard air thread and you will see that all you need is to build a bracket for the vacuum pump under the IP. It will be belt driven if you do this.
 

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Silvertop TD42 with the vac pump on the back of the alternator is a tough side of the track swap. Where my old RD28 was an easy one.

Did anyone ever manage to relocate the vac pump to the TD42 later model setup? or run an external vac pump instead?

The TD42 non vac pump alternator is also an easier find at local repco's etc. if you're stuck.
 

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If you don’t need vacuum for a factory rear diff lock just swap out the vacuum booster for a hydroboost so you no longer need vacuum.
Probably less expensive than swapping out the timing cover etc.
 

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1989 GQ TD42 wagon
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@JFF45 wow, these hydoboosyt kits look fantastic. One of them, then I can run a regular alternator.

only question, what about the clutch?
Not all Patrols have a boosted clutch, so you could go without (whether you remove the booster or not) if you can manage the increased pedal pressure. Not sure what differences there are between the boosted and unboosted setups.
 

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TD42 GQ
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An electric vacuum pump is probably the easiest replacement for the alternator pump.
Reliability? Well a good quality electric pump should be reliable enough and will still work when the engine isn't running.
The downside? It's yet another thing we have to find a place for in an increasingly crowded engine bay.
Is it legal to replace the factory alternator pump with an electric one? Insurance etc?
IF I wanted a larger alternator then personally I'd go for an electric vacuum pump and I'd also wish for a hydroboost set-up for the brakes.
 

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I got the gear driven vac pump setup from a wrecker years ago and put it on my silver top. Needed the sandwich plate, front timing cover and vacuum pump.
I had a coolant leak from the timing cover and destroyed it getting it off so needed a new one anyway.
Think it only cost me $200 but no idea what availability is like these days.
 

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An electric vacuum pump is probably the easiest replacement for the alternator pump.
Reliability? Well a good quality electric pump should be reliable enough and will still work when the engine isn't running.
The downside? It's yet another thing we have to find a place for in an increasingly crowded engine bay.
Is it legal to replace the factory alternator pump with an electric one? Insurance etc?
IF I wanted a larger alternator then personally I'd go for an electric vacuum pump and I'd also wish for a hydroboost set-up for the brakes.
If it's not needed for brake booster, it could be mounted almost anywhere. For my diff lock use it would rarely run once the vac canister has been sucked to max.
 

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If you have onboard air you can just use 14.7 psi to push the diff lock to engage and it's the same as using vacuum to pull it engaged.

You could probably even use a few more psi to create a faster and more positive engagement.
 

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If you have onboard air you can just use 14.7 psi to push the diff lock to engage and it's the same as using vacuum to pull it engaged.

You could probably even use a few more psi to create a faster and more positive engagement.
Have you actually done this? The only info I’ve seen on converting the factory vacuum diff lock to air pressure involved machining internal parts for the actuator and that required removing the diff. Adding the expense of onboard air as well and reinforcing the vacuum lines just makes adding an electric vacuum pump a much easier choice in my view.
 

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Have you actually done this? The only info I’ve seen on converting the factory vacuum diff lock to air pressure involved machining internal parts for the actuator and that required removing the diff. Adding the expense of onboard air as well and reinforcing the vacuum lines just makes adding an electric vacuum pump a much easier choice in my view.
I've seen the a truck with it done, apparently worked fine, although not looked at how it all worked myself. I don't see how atmosphere on one side and vacuum on the other is different to 14.7 on one side and atmosphere on the other so I had no reason to doubt it.
 
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