Airspring Solonoid inner Shaft sanding flat

[wayneg]

It appears a few people have done this to remove the circular indent, http://www.aulro.com/afvb/p38a-range-rover/143260-eas-valve-block-rebuild.html


I want to do this whilst renewing the seals but am unsure how to proceed safely. Can we get a method agreed that is tried and tested. Any disasters, success stories

How critical is it to get it perfectly flat
Can this be done by hand or is a drill press absolutely necessary
Is any material removed ( length ) easily absorbed by the spring.

[Hoges]

You're only removing a couple of thou. I used a cheap drill press because I got given one.. (cheap being operative word for cost and quality) but it was more reliable than my attempting to do it free hand. Actually you can invert the rubber tip and use the "new" side if this hasn't been done previously :eek:;)

[wayneg]

Please tell me more about the invert option, How, is it glued down, potential damage etc

[davidsonsm]

How do you get them out without damaging them?

I used a hand drill in a vice. Mine were still concave but I removed the indent. Turning them over sounds like the plan.

[Robsrod 58]

Wayne,
I brought this up in your other thread and asked if any one had any " tested "success. I should mention that I have done this but it is my spare valve block so as yet untested in the Hoover. As I'm one to leave things alone while it's working I'm not game enough to test providence. I tried to remove the rubber first, but wouldn't budge. So;

My method was also to use a drill press (it would be extremely difficult to get a perpendicular flat surface without it ) and 1200W&D paper wet and then followed with brasso to achieve a final finish. The best way would be to use a high speed lathe and liquid nitrogen to freeze the rubber, everyone's got that stuff havn't they! If I recall I had to remove about 10 thou to eliminate the groove. I did all solenoid valves in the block. I'm very confident of success but testing will prove

If any one in the Sydney area is having valve block problems and wishes to give mine a go they are welcome, or if someone can suggest a way of testing mine without installing it I will do that, at least then we will all know if this method works.

Rob

[davidsonsm]

I must admit, I'm still puzzled by their ability to seal at all. Given the weakness of the spring and the fact they're energise to open. I guess it comes down to pressure differential across the seat. What is it?

[Robsrod 58]

I must admit, I'm still puzzled by their ability to seal at all. Given the weakness of the spring and the fact they're energise to open. I guess it comes down to pressure differential across the seat. What is it?
I think the spring is only there to get the valve stem moving the right way, air pressure take over once seated.... I think. If you think about it, it must work something like this otherwise new valve blocks would wear out on the shelf!

Rob

[davidsonsm]

Think I'll have a play around with one of the spares I have.

Anybody know how to test the hardness of the rubber? I'd imagine that's quite important.

Assume I can use a hole punch to make a new tablet, but it obviously needs to be the correct diameter.

[Robsrod 58]

I don't think there made of rubber, more likely neoprene or some other synthetic that won't age rot or deform too much I suspect.

Rob

[Robsrod 58]

Oh, I forgot to ask did you get the insert out without damage?

Rob

[wayneg]

I have splashed out $86 on a drill press on special.
Taken the plunger from the diaphragm solenoid put in the drill and gently run it up and down onto a well soaked fine carborundum oil stone. Once the indent was nearly gone I then went to 1500 wet and dry for the final bit. ( could not get 2000)
As advised this seems to work well, is controllable with the assurance that the final surface will be smooth and relatively flat. I am happy with the result so thanks for the advise, I cant believe I missed the previous posts about doing this.
I did try to remove the rubber but no way, its definitely anchored.
I could take some pics when I do all the others if anyone is interested

[Robsrod 58]

I have splashed out $86 on a drill press on special.
Taken the plunger from the diaphragm solenoid put in the drill and gently run it up and down onto a well soaked fine carborundum oil stone. Once the indent was nearly gone I then went to 1500 wet and dry for the final bit. ( could not get 2000)
As advised this seems to work well, is controllable with the assurance that the final surface will be relatively flat. I am happy with the result so thanks for the advise, I cant believe I missed the previous posts about doing this.
I did try to remove the rubber but no way, its definitely anchored.
I could take some pics when I do all the others if anyone is interested

Wow, 2000W/D you must have patience:D:D

Rob

[davidsonsm]

Reversed the rubber tablet/pill today on two solenoid valves. Boy, they're not easy to get out. But by gluing them back proud, you can sand them back flat. Not sure if they'll seal any better. The rebuilt valve block I have installed is pretty good as is at present.

[Robsrod 58]

The rebuilt valve block I have installed is pretty good as is at present.

Yeh, thats why my rebuilt block is in bubble wrap and not on the car.:D

Rob