Power Steering Reservoir Cap

Saloons
1

Evening all,

Wondered if anybody had a part number / interchangeable suggestion for the cap on the PAS reservoir. The one on my car is fine except it was a bit rusty and so has been painted. Following a bit of a restoration splurge this last few weeks, a shiny zinc plated example would be good.

Thinking aloud, is the bayonet fitting the same as the petrol filler, and so a polished ally one might suit?

Thanks in advance.

2

http://www.cjponyparts.com/power-steering-pump-cap-for-straight-neck-power-steering-pump-chrome-1965-1966/p/PSC14/
This should work for you. 1965-1975 Mustang if you look it up at your local auto parts store.

3

Thanks, although I might struggle to find a UK supplier. I had stumbled across this item (or similar) and did wonder. Will let you know.

Thanks again.

JC

4

I think it’s the same size as a radiator cap.

5

On checking, the tabs are different; the existing reservoir cap has the tabs pointing in from the edge, whereas this has them pointing out form the centre. Basically what I need is a radiator cap without the thermostat / pressure bits.

6

If it is like the one on my 1965 3.8S, I believe what you need as a radiator blanking cap as was fitted to the radiator for the BMC 1100/1300 range since they had a separate overflow tank that had the pressure type cap. See Ebay item number
272174429499. There are many available, some may even be available in chrome if you want to go fancy…

7

Thanks John. I’ve taken a punt on a nickel plated oil cap for a Triumph Vitesse; images seen online seem to be just what I’m looking for so have ordered one for GBP1! I’ll let you know.

8

Note that the original cap has a small vent hole in the rubber seal gasket. I found out that this hole is very important as I re-plated my cap and re-assembled it with a hand made rubber gasket manufactured from sheet rubber from McMaster-Carr. When placed into service, the P/S reservoir would pressurize and would force P/S fluid out between the reservoir lid that the reservoir canister. After re-sealing the lid 3 times trying different seals and seals with sealing compound, it still leaked in operation. I compared my replacement cap seal with the original seal (glad that I kept it) and I discovered that there is a very small crescent moon shaped vent hole in the rubber rubber seal gasket. This relieves any pressure that builds in the reservoir from the returning fluid and it enables the lid to canister seal to seal as it should. Our P/S system is now leak free.

Good luck.

Brian

9

You must have read my mind.

The cheap replacement fits fine and polished up well so now we know the fitting is an almost universal 1960’s oil cap, but I wondered also about the pressure build-up as the fluid expanded when warm. I observed the same crescent shaped ‘cut’ in the seal of the original, and so have cut a ‘v’ in the seal of the new cap so there is an air route betwixt fluid and atmosphere.

Finding the cheapy and confirming the fitting means I may also have to buy a polished stainless version…