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MG MGB Technical - Removing Brake Master Cylinder cover

What could be simpler - undo the 4 screws holding down the cover?

Well, lots when the offending screws are rusted solid and someone has been there before and rounded off the + heads!!

The nuts do not appear to be welded into captivity so I was wondering if any one knows for certain out there if they are recess slotted into position. If so, I can just grind/cut them off from below with impunity and replace with a new set.

Advice welcome please.

Thanks

Paul
Paul Barrow

Paul - First, try using a posidrive screwdriver rather than a plain Phillips head, although the PO may well have replaced the screws with with Phillips head screws. All of the screws should have a captive nuts (or a threaded boss) on the under side of the shelf, only one screw has a free nut on it and that is the one that has the cable clip on it for the sires going over to the dimmer switch and that nut is just there to hold the clip, the screw itself goes through a threaded boss first. If the screws are really bad, it is possible that you will have to drill them out and helicoil the bosses for new screws (10-32). Cheers - Dave
David DuBois

Thanks Dave. The heads are almost round holes - I think I am going to have fun finding a long enough drill bit to get into them! Danger is, of course, at that length there is going to be tremendous pressure on the bit!

Ah well!! British Cars eh?

Paul
Paul Barrow

You can also cut the heads off using a Dremmel tool or die grinder with a stone or a carbide burr.
J Heisenfeldt

I had the same problem a few years ago. The nuts (on my '73 BGT) do seem to be welded so after thinking long and hard I concluded that if I used a really long drill I could remove the screw heads, then disassemble everything in the pedla box leaving plenty of space to drill out the remains of the screws and retap the nuts if necessary. So that's what I did, except that once I had room to work I found that the heat of drilling heat freed the screws and there was just enough left to get a vise grip on and wind them out. I replaced them with stainless steel coated with copper grease, and now just ease them every year or so to make sure they will come out if/when needed. I hope you're as luck as I was! Oh - the drill I used was a really long multi-purpose bit with a diameter large enough to cover the whole screw head. It's tucked away somewhere in the workshop and I'll look it out and find the size if you need that.
Miles Banister

Oh - one more thing. I have a vague recollection that the screws protude below the nuts enough to get a vise on them. It occurred to me (after I'd got them out) that maybe I could have loosened them using that method and avoided all the drilling.
Miles Banister

You may do best to grind the captive nuts off and when replacing use a nut and bolt, oh and an assistant!
Stan Best

You can try to use a good quality left hand drill bit and go right into the center of the screws and sometimes the reverse action will turn the screw out. Hit them with plenty of PB Blaster in advance.
MK Mike

I managed to get a nice, long steel drill bit and was able to drill through most of the screws quite centrally and as Miles suggested the heat freed them off sufficiently to enable them to be wound out from below going upwards. Once I could no longer get a decent grip on the screw I was able to get on the head with a pair of medium length pliers. Thanks everyone for the tips. When it goes back together there will be a ton of anti-sieze used!

Paul
Paul Barrow

This thread was discussed between 08/05/2008 and 13/05/2008

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