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PDWA Seal Bolt Removal Method

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jjbunn

jjbunn

Jedi Knight
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The bolt that seals the chamber on the PDWA is tough to remove. Here's what worked for me:

1) Don't even think about trying to remove it before applying PB Blaster to the joint for a couple of days: you will give yourself a hernia.

2) Take the 7/8" socket of a tyre iron, which fits the bolt head, and a rubber mallet, and place the PDWA bolt head in the tyre iron. Hold the pair on the bench with one hand.

3) Tap the PDWA body with increasing force with the mallet. After a few bashes, it comes off.

(BTW can someone please explain in what situations copper washers are used, rather than steel?)

I have refurbished my master cylinder: the end rubber seal was perished, hence the leak. The bore looked clean as a whistle. The nice refurb kit from TRF includes red rubber grease, which I slathered generously over everything before replacing the parts. This master cylinder is *much* easier to disassemble than the MC in the MGB.
 
One of the places you will find copper washers is as a seal for hydraulics. As you torque down on the fastener, the copper is crushed providing a leak proof seal.
 
Just wondering, does your 71 shuttle valve use the o-ring or the wider seals?
 
poolboy said:
Just wondering, does your 71 shuttle valve use the o-ring or the wider seals?
Click to expand...

They look more square in x-section:

1940121380_d78d647e6c.jpg
 
yes, the originals.
 
Brosky said:
Here's some more pictures of the rebuilding process for these valves. I had no problem getting my end bolt loose after soaking in WD40 for 24 hours.

https://www.britishcarforum.com/bcforum/ubbthreads.php/ubb/showflat/Number/359434/fpart/1
Click to expand...

Nice! I want to get mine to bare brass, which I love the colour of. I like the way you painted the bolt head red!

I think my rubber gaskets are in excellent condition, so I'm going to leave them alone. I have a nice new copper washer for the bolt.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I think my rubber gaskets are in excellent condition, so I'm going to leave them alone. I have a nice new copper washer for the bolt. [/QUOTE]

Julian,

How old are those seals? If one of them starts to leak, you will have fluid coming out of your switch. Not a good thing for the price of the kit and the fact that you have it all apart. Moss sells the kits, part number is in the picture of my thread.

Good old Brasso works just fine for the brass clean up on the OD.
 
I agree with Paul, those rubber gaskets were originally round o-rings. Get the kit. Once the valve body is polished, powder coat it with clear.
 
Brosky, I noticed in the pics that there were 4 o-ring seals in the plastic pack. Were they of different sizees?
 
PB,

Yes, there are two different styles of seals. Mine used the fully round (donut) O-Ring style. They give both because I think that this valve may be used on other cars.

EDIT: Let me correct myself on this one. There are two different style PISTONS, hence the two different SIZE o-rings. Sorry, I'm getting old and it was over 10 minutes ago that I did that job.

See attached instruction sheet:
 
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