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MG MGA - Float chamber grommet seals

I have recently bought some replacement seals for my SU H4 carb float chambers as the seals originally fitted have gone really soft and begun to swell and leak.
I believe it is the modern unleaded fuel which affects the old seals in this way.

I have made one attempt at fitting the new grommets (part no AUC 1534) but they are very much more rigid than the original ones and I found that it was impossible to compress them enough to get the banjo bolt to bite onto the threads.
I was using a socket on an extension from below to try put enough force behind it to allow the threads to engage.

Is there a trick to fitting these that anyone can tell me about so that I can get these grommet/seals to fit without using excessive force and damaging something?
(Lindsay, I need your expertise here!)

Cheers

Colyn
Colyn Firth

Colyn,
There appears to be various sources of these grommets - some that fit and some that do not. I returned a set I had bought (they were hard like you describe, and no way were they going to fit), and they were replaced by a softer set that did indeed fit. This was a couple of years ago, so it seems that the problem persists.
Peter.
P. Tilbury

Colyn

I had no issue with the set I fitted a couple of months back. I got them from Bob West.

Prior to that I had posted a photo on this forum showing some other part of the carb set-up that someone wanted to view and an astute observer noted that my grommets looked cracked and worn. When I replaced them, the cracking was all external; the contact areas were still okay, but you can never be too safe in these areas.

Steve
Steve Gyles

Colyn, I struggled with mine as you have. I ended up taking the carbs off the manifold - I managed to slide them both off together as a unit - and then replaced the grommet whilst on the bench - a lot easier that way - you can tidy up the manifold and heat shield whilst you are at it ! - actually noticed mine has started weeping again 5 years later so the new seals are not what they used to be ( or did the originals only last 5 years too?) cheers Cam
Cam Cunningham

Colyn, I don't remember having any trouble fitting mine, I think I got them from Moss, but my spare set came from SU. I would think mine have been in service for at least 4 years, but not the slightest leak from them....yet! I always use the ordinary unleaded in my car, but I think there may be an issue with the "super" unleaded fuels and rubber (or is it neoprene?) seals.
You could try lubricating the new seals with WD40, making sure that they are fully seated in the float bowl casting, and then slip the similarly lubricated bolt through the seals.
Lindsay Sampford

This thread was discussed between 19/01/2011 and 21/01/2011

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