iandvl wrote: ↑25 Feb 2022 09:01
A final post on this matter - with some photographs.
I just felt I had to make the post, as the amount of foresight and care that was involved in the design of the Y61 (and presumably the other variants as well - but I don't know them as I know my Y61) never ceases to amaze me.
The vacuum system on the Patrol comprises of (in my case) two pods / canisters just in front of the difflock solenoid close to the firewall on the passenger side of the engine bay. The vacuum is created by a steel pipe from the intake manifold, and all rubber hoses have non-return valves in place. The pods are there to maintain vacuum so that it should still be possible to press the clutch and brakes relatively easily even when the vehicle is off. As with all things vacuum, I don't think it is always perfect - should the vehicle be off for a while, I'm sure the vacuum will leak and this will result in the clutch being harder to press if the vehicle has been off for a while. When starting the vehicle though, the vacuum will build up again and the clutch will be softer thereafter. I read many reports of this from our Boggan friends in Oz yesterday whilst reading up on my possible issues. I can also remember experiencing the same thing on the one or two occasions when my truck has been standing for a bit. One can literally feel the clutch get softer as one starts the vehicle.
In any case, the one pipe on the left-hand pod was broken off. There was an indication that it must have been repaired quite recently, based on the glue at the base. As I mentioned before, I'm not going to dwell on that.
I stuck the pipe back on using super glue after which I gave it a liberal dose of epoxy. This has worked - the clutch is fine again now. Anthony has a spare vacuum pod for me, and I'll collect it at some point and install it.
I think the only thing I'm confused about is that although my clutch was very stiff, the brakes were totally unaffected. And yet the various diagrams I've seen on the TB45 motor indicates that the brake booster should run off the same pod as the clutch. This makes no sense, so I'm going to have to see exactly where the brake booster vacuum pipe is connected. Perhaps it runs from the other pod ? I shall investigate this at some point in time.
This is a photograph of the broken pod.
Broken-1.jpg
And this photograph should illustrate the non-return valves on the rubber pipes. The yellow arrows on the pipe indicate which way around the pipes should be and there is also a visible thickening of the pipe at these locations. These thicker bits are the non-return valves. If you remove the pipe and blow through it, you will only be able to blow through it in one direction. One can also note the liberal amount of epoxy around the broken pod in the background of this photo...
Non-Return.jpg
In any case, I'm happy it was not a collapsed diaphragm. And I learnt something new yesterday too. And, as I mentioned earlier, the design decisions made during the design of the motor and relevant peripherals is absolutely astounding.