7 replies to this topic

[goat64]

Hi all

 

Went to change cylinder on my 1976 850cc mini, to be thwarted by the smaller or the 2 bolts securing it to the back plate.

None of my spanners seem to fit snugly.

 

A 5/16" is too tight, and a 9mm is too loose.

I think the bolt should be a "1/4 inch UNF 3/8 long" (part number on minispares is SH604031), but a 1/4" hex spanner is way too small.

 

It's a bit corroded, and I expect to spend a while with some WD40 and some gentle tapping to free it, but do't dare be too "forceful" unless I have a really good fit on spanner.

 

Anyone confirm what size hex / ring spanner I should be using?

Any other tips to get it out?

 

The larger bolt has come out fine.

 

I guess I can always change the whole backplate with offending cylinder still bolted on, but it seems a bit excessive for 1 stuck small bolt.

 

Thanks in advance

 

Goat

 

 

(1976 mini 850 saloon - with twin slave cylinders on each front wheel. The offending bolt is on the trailing cylinder)

[nicklouse]

put the WD40 down and find some release agent like PlusGas.

[ukcooper]

Do what the men say for a few days I lkie 3in1 oil and or plusgas but wd40 smells best to me

Edited by ukcooper, 09 March 2018 - 02:11 PM.

[ings]

heat the bolt up with a heatgun...

[nicklouse]

size for the 1/4 UNF should be 3/8 AF IIRC

[richmondclassicsnorthwales]

I stock these, so when your done removing, if you want replacements give me a shout - PM me

 

We only charge  £1.20 p & p. no vat,  small bolt + washer 45p  larger 90p + washer

 

Regards Neil.

[Spider]

size for the 1/4 UNF should be 3/8 AF IIRC

 

Not sure if it was the same in the UK, but our were something oddball like 7/32" AF.

[goat64]

SOLVED:

 

Hi guys

Thanks for all the advice - helpful as usual.

 

In the end, found a 2-BA hex socket was a perfect fit. Not sure how this matches up to 7/32" and it certainly didn't fit a 3/8" socket. I found out a 2BA is 8.25mm, and doesn't map to any AF size.  This site is the source:

 

http://www.baconsdoz...sion charts.htm

 

Stupidly, I had made a note of this after hours of fiddling around when I changed the other side cylinder 4 years ago.

 

It is pretty tragic when you get to the stage of not being able to remember what spanner to use after hours of struggling, so you write it down for next time to save hassle, then you forget that you've written it down !!!!    Just off to write myself a note to check the note I made last time if I ever need to change the darn thing again.

 

Thanks to Neil for offer of new bolt, but despite my best efforts to to damage the head, it seems perfectly servicable still - will bear it mind for next time.

 

Cheers again

 

Goat

 

1976 mini 850 saloon