So the door motor in my RMF hasn't been working since the late 90s as far as I have been told
I was also told it definitely needs replacing, when I brought the bus!

Finally after getting 3 hours of taking it apart and investigating I found the 2 issues!
1) seized brushes
2) brush spring missing (found in the bottom of the housing)

So fixed them, put it back together and after greasing; woooooooo it worked first time!

Now just to wire it up! but first when it was disconnected from the electrics bolts were lost that hold the micro switch panel in place and the nuts that hold the wires to the motor.

Does anyone know thread they may be, i think they might be 2BA from my calculations but wondered if any other RM owners with doors knew?

My bus number (if any): RMF2771 (RCN701)

BA thread sizes are quite common for the smaller fixings on RM's - Try www.namrick.co.uk for imperial thread stuff. or

http://www.chronos.ltd.uk/acatalog/Steel_Hex_Head__one_size_smaller__BA_Bolts.html

My bus number (if any): RML2747

I won't attempt it but could we have a nice simple, preferably illustrated explanation of door motor electrics?:)

hi Roy,

What sort of explanation are you after?
how it should be wired?
How the motor works?
or what i did to fix it?

then I will be happy to attempt to explain

My bus number (if any): RMF2771 (RCN 701)

The door motor on an RMA or RMF is ( with the seat frame removed an easy to access unit. A but harder on RMC and RCL.

They are quite a simple unit in that they are almost the same as a Lucas windscreen wiper motor from the same era. Only bigger with a different coupling and less fiddly.

Properly greased and lubricated and as long as the motor is clean and in good state they will function very well.

But they have one achilles, they have to be set up to operate perfectly.

The smaller bolts should be BA but check carefully as they may be UNF or even whitworth as some components came off the shelf from different suppliers and a few were still using older conventions right into the 1960s.

The stop and start points need to be set and adjusted to a high degree of precision.

I've never seen a set of directions on setting the spacings ( a bit like setting a track rod end) but trail and error has to be done very carefully as get it wrong and you could break it first go.

If they are not, the overun on the motor causes enough torque to crack the unit housing or the pivot arm.
This is often such a fine crack that it is not visible unless watched carefully whilst operating. It will continue to work but the doors will not fully open or close evenly.

Obviously all the pivot points on the doors themselves need to be checked they they are moving freely and properly lubricated and kept clean.

If anyone has the procedure or correct technique as published it would be really useful to have it posted here or in the RMOOA magazine. It must be similar for RMCand RCL but I've only done this on two RMAs and a long time ago now.

The RMC door motors are the same as those used in the GS and MBA, probably with similar wiring. I'm not sure of the setup on the RMF, but presumably the same linkage as the MBA.

I have the RMC wiring somewhere and an RMC LT bulletin which may cover door setup.

My bus number (if any): RML2532

having never seen how other type RMs doors work/motor types i can only speak for my type.

so for Mark's comment

having had the entire mechanism apart, on my type there is a Clutch, (presumably for the emergency opening as labelled on the door with the push here stickers) if this isn't over tightened this should take care of the overrun.

The clutch on mine is a very simple 3 plate friction drive (2 drive (Motor side and doorside and slave plate squashed in the centre), pressed down using a spring tightened by the bolt in the centre of the pivot point in the video.

If you loose then right off, I could stop the armature moving with my hand with the motor resting unsecured on the floor and still rotating. So I would say if going to try trial and error, then loosen off (but not all the way) the clutch so it will still grip but slip easily if required

Though this could be because I took it apart and cleaned it, therefore ensuring the clutch plates hasn't seized into one solid plate.

My bus number (if any): RMF2771 (RCN 701)