10 replies to this topic

[claysummers]

Is anyone familiar with these, specifically - dismantling the piston and valve body? I have removed the circlip, manipulated piston shaft and tried some compressed air without so far managing to move the brass retainer.

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[dattoman]

Yup

 

I'll get you some proper breakdown pics

I think its a "yank it out and replace the parts you break" scenario

[claysummers]

Thanks Neil. I thought you would.


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[claysummers]

I ended up getting it apart without damage. It was very tight though, brass in aluminium. Probably could have used some heat.

No markings on it but the bore measures 5/8" which was enough to identify it and get a minor service kit from Power Brakes SA, which was $104. Not much in there really, just a few little bits of rubber, gasket and filter foam.

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[dattoman]

Yes PB are good to deal with

 

 

 vh40.jpg   178.94K   2 downloads

[claysummers]

Thanks Datto, that will be most handy.

I always recommend them, though they have got fairly dear, it's just the way of the world. My first conversion to disc brakes in 1985, they helped me sort when I had the calipers on upside down. The guy had an EH and knew the drum.

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[Dr Terry]

 My first conversion to disc brakes in 1985, they helped me sort when I had the calipers on upside down. The guy had an EH and knew the drum.

 

He knew the "drum". Was that supposed to be a pun  

 

Dr Terry

[claysummers]

He knew the "drum". Was that supposed to be a pun  

 

Dr Terry

negative, caster 

[claysummers]

I ended up replacing all the seals in the 5/8" cylinder and 5/16 valve. New valve rubbers were very tight but went in. Diaphragm had a slight tear which I may have done taking it apart.

Bled up ok but vacuum is locking the brakes. I've apparently cocked up the vacuum valve operation in my stumbling refurbishment. Back on the bench. Old cars I don't know......


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[yel327]

At least you can fix it Clay! Everything on modern cars is far more complicated.

[claysummers]

It turns out that the 3/16" piston appears to be leaking pressure. I believe Power Brakes have given me two number 25 cups, instead of a 25 and a 25A. The 25A has a smaller shaft hole to cater for the reduced shaft diameter. Coupled with the cups being quite a tight fit, rather than slide, pressure is bypassing. That is my theory. So I swapped the 5/16" with another from the VH44 I had fitted previously, and brakes are now working well.

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