difference in brake drums with different wheel bolts?

for those with Series MM sidevalve cars produced between September 1948 and February 1953
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TvdWerf
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difference in brake drums with different wheel bolts?

Post by TvdWerf »

My MM has at the front other wheel bolts as rear, but I have a complete front suspension with the right ones.
I ordered new bolts at ESM, but am wondering if only the drums are different, or the complete suspension?
Are the brake cylinders and shoes also the same?
MM '51 LHD sidevalve
mike.perry
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Re: difference in brake drums with different wheel bolts?

Post by mike.perry »

Early brake drums had BSF threads, later drums had UNF threads
See http://seriesmm.mmoc.org.uk Technical info, front suspension stub axle and wheel bolt threads
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TvdWerf
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Re: difference in brake drums with different wheel bolts?

Post by TvdWerf »

I know the drums have different threads, but to get the other drum on the car, do I need to change only the drum, or also the other suspension parts?
My rear axle has the UNF bolts, and front the BSF, my spare suspension has also UNF bolts.
I like to drive with front and rear the same bolts.
When not need to change, I like to keep the good working brake cylinders, and wheel bearings :D
MM '51 LHD sidevalve
TvdWerf
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Re: difference in brake drums with different wheel bolts?

Post by TvdWerf »

At ESM I see 2 different bearing Kits, from 1948-1949, and 1950-1954, is this the difference also between BSF and UNF?
The only other way to check is take the drums from the car, and when possible, I do this at a later moment, not now..
MM '51 LHD sidevalve
mike.perry
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Re: difference in brake drums with different wheel bolts?

Post by mike.perry »

The drums should fit on either side, you just have to keep the bolts to the matching brake drums.
Change BSF to UNF threads car LHD 126725, RHD 131858
Last edited by mike.perry on Tue Apr 05, 2016 4:33 pm, edited 1 time in total.
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smithskids
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Re: difference in brake drums with different wheel bolts?

Post by smithskids »

You only need swap the brake drums. I have changed axles in the past and the only difference was I had to re-adjust the brakes as the older drums were slightly more worn. Apart from the thread size for the wheel bolts they are identical. :D
TvdWerf
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Re: difference in brake drums with different wheel bolts?

Post by TvdWerf »

my (LHD) chassisnumber is 122061, but rear UNF, Front BSF.
I got the car with an extra front suspension with UNF, so this means the actual BSF is original?
I will start the job in a few weeks, maybe first to order 2 new bearingsets at ESM...
MM '51 LHD sidevalve
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