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MG MGB Technical - Rubber bumper

I need some advice for the assembly of the new metal parts to the old rubber bumper. Can anyone help please.
M.J. McCartney

I did a couple of rear bumpers last year.

Are you doing the front or rear? Have you removed the old steel parts from the rubber yet?
Brian Shaw

Hi Brian, Many thanks for the contact.
Rear bumper.All old steel parts removed( 'fell off'!).
I think it was originally riveted together but cannot manage the same.Bolts possibly but access is a real problem.
Mike
M.J. McCartney

If you haven't already bought new parts, this is what you'll need:

Rear armature BHH 1821
Clamping plate (upper) BHH 1550
Clamping plate (lower) BHH 1551
Rivet CHA 307 - 28 off
Stud FHS 614 - 5 off (to mount bumper to body) + nuts and washers
Bracket - side fixing BHH 1575 - 2 off + nuts and washers
Spacer for side fixing BHH 1576 - 2 off

MGBhive are currently offering the armature, clamping plates, and rivets on eBay http://www.ebay.co.uk/itm/150869368067?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Pop-rivets are 3/16" x 1" and are much cheaper from a hardware store than 'specialist' MG suppliers. You say that you cannot rivet the assembly - I found this quite easy to do (except for one rivet each side of the top clamping plate, which was difficult to access - I just left that hole unriveted). A couple of guys posting on this site have used self-tapping screws instead of riveting - check the archives for thread 'Rivets in rear rubber bumpers'. If you prefer to use bolts it may be possible to tap the 3/16" holes in the armature to say 1/4" UNF as long as you're careful not to overtighten and strip the threads.

If you want your bumper refurb to last a few years, give the new parts a good coating of Waxoyl or similar (including inside the armature).

Very soon I am going to refurb a front bumper, but instead of using clamping plates I have bought some large diameter marine grade stainless washers, which are certainly cheaper and hopefully longer lasting than the clamping plates, which are always the first part to rot.
Brian Shaw

The clamping plates are a bore - they always rust. The answer is to galvanize or better still; a large galvanized washer for each rivet or self-tapping screw.
R Walker

Wow ! I've never heard of anybody buying a brand new armature, or cover. Secondhand bumpers in good condition are reasonably cheap and plentiful. Clamping strips maybe will need to be changed.

I don't know what is supplied for the rivets these days but originals were steel. You wouldn't fix those with hand operated tools. Our local MG specialist used to take bumpers to a commercial vehicle body maker, who used pneumatic tools to fit them.

I've previously used good quality alloy rivets from a specialist fastener supplier; you want a good sized clamp area and suitable grip length, probably not easily found at a general hardware shop.

Using individual washers instead of the clamp strips possibly might allow a bit of 'rippling' in the cover between rivets. But, one of mine has a couple of washers where a strip had corroded and is ok. Any more and I probably would have considered stripping it and replacing the strip.


J N Gibson

The rivets supplied by Moss are alloy, as are the ones I bought from Grahams Machinery (see photo, Grahams at top, Moss at bottom).

Description for the Grahams rivet is: 4.8 x 28.2 aluminium pop rivet, 4.8mm to 19.8mm grip range, part number AVD-1661-0631.

Screwfix also do 4.8 x 25mm pop rivets, but only in packs of 250.

The washers I have bought for the front bumper rivets are eBay item http://www.ebay.co.uk/itm/310293293569;jsessionid=18E76D1A25FEFDF0219853210E3169AA?ru=http%3A%2F%2Fwww.ebay.co.uk%2Fsch%2Fi.html%3F_sacat%3D0%26_nkw%3D310293293569%26_rdc%3D1

Brian Shaw

Although the rubber bumpers add considerably to the strength of the shell, the original chrome arrangement was also strong for its size albeit prone to irritating minor damage. If you give some thought to the reconstruction of your bumpers, you can save some weight by reducing the size of the armature and still keep most of the benefit of the rubber.
R Walker

This thread was discussed between 13/08/2012 and 16/08/2012

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