MK3 rear MC cap

[Britbike850]

Anyone make a aluminum rear master cylinder reservoir cap for a MK3? Or know the size and thread?
Thanks,
Rod

 

[EstuaryBoy]

Not sure if it helps, but AN list front and rear replacement caps as the same part number..
(I've changed both M/Cs on my Mk3 so can't remember exactly what material the originals were)

 

[Torontonian]

Not sure if it helps, but AN list front and rear replacement caps as the same part number..
(I've changed both M/Cs on my Mk3 so can't remember exactly what material the originals were)

The rear is made of real genuine plastic , with some big grabby points.
I'd like to fit polished aluminum on the rear too , just for looks.

 

[Britbike850]

I am pretty sure the rear reservoir cap is a different size and thread from the front cap
still looking
Rod

 

[L.A.B.]

I am pretty sure the rear reservoir cap is a different size and thread from the front cap

No, the Mk3 caps and threads are (or should be) the same.

 

[L.A.B.]

...And the caps have the same part number 06-5740...

...although that cap is no longer available.
Replaced by...

Andover Norton - RESERVOIR CAP M/CYLINDER (60.4365)(99.2751)(3847-240) - 06.5740

RESERVOIR CAP M/CYLINDER (60.4365)(99.2751)(3847-240)

andover-norton.co.uk

 

[Mart UK]

Telephone Andover Norton. They still sell complete units, so the cap may be available separately, if that's what you decide to go with. I needed a spacer, not listed separately, I spoke to them and they were able to supply just that part. As it's listed separately, they may be willing to break a kit? They may be able to give you dimensions / thread too. Worth a try.

 

[Torontonian]

...And the caps have the same part number 06-5740...

...although that cap is no longer available.
Replaced by...

Andover Norton - RESERVOIR CAP M/CYLINDER (60.4365)(99.2751)(3847-240) - 06.5740

RESERVOIR CAP M/CYLINDER (60.4365)(99.2751)(3847-240)

andover-norton.co.uk

O.K. so why a hole in the center of the new cap ? To let the rain in ?

 

[dobba99]

Actually its to let air in. The original cap has a air vent hole but its not as easy to find! It enters the cap from the side. I made an aluminium alloy cap for the brake bleeding kit i use when servicing the brakes. Due to the fact a buttress thread is used to fasten the cap and that its a blind hole it was a pain in the arse screwcutting it. Would have been easier using a new plastic cap and open the vent hole up to fit the bleeder kit.

 

[L.A.B.]

O.K. so why a hole in the center of the new cap ? To let the rain in ?

Yes, same as the earlier metal cap.