Oil pump - leak from pressure relief valve - Arrrggggghhhhh

[Always wanted a Stag]

Can anyone help me ?

I have a slight, but VERY annoying leak from the pressure relief valve incorporated in the oil pump.

I have fitted a new O ring twice recently using an O ring from two different Stag spares suppliers just in case there was a difference that would help.

On both occasions, the new O ring worked like a dream for about three days whereupon ...... drip ....... drip ....... drip ....... etc

It's driving me MAD.

Is there anything that I'm doing wrong ? Should I be applying grease to the O ring pre-fitting etc ?

Is it possible that the pump or the cap (onto which the O ring fits) is damaged/scored - couldn't see or feel anything wrong.

I've virtually resigned myself to having a new pump to save what is left of my sanity.

Thanks for any suggestions

Paul

[Mark Shutt]

for the sake of how much a new pump costs it will indeed save your sanity and give you piece of mind too!

[Guest]

Hi Paul,
It seems most old English vehicles tend to leak some oil.My stag has a few odd drips but I make sure the drip tray is well placed under the car.The auto is the worst.Sometimes there is nothing and then next week after a run there is lots!!!!
I understand it depends where the torque converter stops when the engine is turned off as there is a relief valve in them.If at the bottom it leaks back into the transmission housing.My Matchless twin also leaks from between the crankcases but some sponge rubber fitted up underneath tends to absorb the oil. If it ain't broke. Don't fix it is my reasoning
Anthony
L

[Staggard]

Hi Paul,
It seems most old English vehicles tend to leak some oil.My stag has a few odd drips but I make sure the drip tray is well placed under the car.The auto is the worst.Sometimes there is nothing and then next week after a run there is lots!!!!
I understand it depends where the torque converter stops when the engine is turned off as there is a relief valve in them.If at the bottom it leaks back into the transmission housing.My Matchless twin also leaks from between the crankcases but some sponge rubber fitted up underneath tends to absorb the oil. If it ain't broke. Don't fix it is my reasoning
Anthony
L

I've never heard of a valve in the converter, there is an converter check valve in the valve block. Graham

[flying farmer]

A bit of grease on the O ring before reassembling might help. Look carefully at the one you take out, if it has a nick out of it there is probably a sharp bit of casting catching it as it goes in. If the O ring looks perfect then there is a possibility of a score in the pump casing letting the oil past.

Neil

[wilf]

It might not be actually leaking from the pressure relief valve itself. I found that all leaks from oil pump and transfer housing O rings show up there, even some rocker cover leaks made their way down there, it seems to be like a in magnet for leaked oil from all over.

[Always wanted a Stag]

Thanks for the responses.

I know what you mean by ..... old English vehicles tend to leak some oil.

I'm pretty certain that the oil is coming from the pressure relief valve area but I'll do a bit of investigating before I go to step two which is try the third new O Ring, checking first the old one for any obvious signs of damage before gritting my teeth for a change of pump.

I the meantime, careful positioning of a drip tray will be the order of the day.

Paul

[Guest]

Hi Graham,

I have been told that there is a valve of some sort in the converter that can tend to cause the type 35 auto to overfill due to leakage from it!!! I had better do some investigation into this.Thanks anyway for the info.

Anthony

[wilf]

See post #4. It is a non-return valve within the gearbox that fails, and allows the torque convertor oil to drain back into the 'box and flood it. As Graham says, I don't believe this valve sits within the TC itself. Sure I saw a schematic of the BW35 somewhere that showed it.

[tractorjames]

You could try a hardware or motor factors they often have selection packs of o rings and maybe find an o ring that's the same size but "thicker" rubber.

James

[Always wanted a Stag]

Thanks James.

I might give it a go as I have one final standard O ring as a pattern.

Paul