Steam leak from reverser block

Joe · Post by **Joe** » Tue Jan 20, 2015 4:03 pm

Hi, on my mamod there is a steam leak from the reverser block and the reverser handle is very loose to move, the loco still functions in forward and reverse gear but steam is escaping, has a seal gone or does it need just tightening up (and if so which bolt)?

thanks in advance
Joe

steampig · Post by **steampig** » Tue Jan 20, 2015 5:42 pm

1) The reverser switch plate is tightened to the body against the spring on the long axial shaft - I'm not sure I can see a spring on that in your picture, but maybe it's there. If there is no spring, that's your problem. If there is, tighten the nut a bit, or manipulate the spring longer - or possibly the shaft has come loose in the switch plate and needs screwing back in. The lever should not be loose but hold its position.

2) A drop of steam oil between the reverser plate and body before each run assists the seal and also gets a bit of oil into the cylinders if you have no lubricator

There can be other faults with the reverser ... see 'locomotives and railways' at http://modelsteam.myfreeforum.org/ where they know everything there is to know about sorting Mamod locos.

DLRdan · Post by **DLRdan** » Tue Jan 20, 2015 8:19 pm

Since you said there had been a fire down there I would suspect that the spring has been damaged by the heat. You might get away with stretching the spring slightly but its probably best to find a new one. One possible place to find one is a ball point pen, the ones that click. Sounds strange but one of my locos runs with those springs on the cylinders and they have been fine for years. While you are replacing the spring is a good idea to change the o rings too.

Joe · Post by **Joe** » Wed Jan 21, 2015 3:44 pm

so should the screw with the spring on screw out or do i need to take the whole reverser block out?

cheers
Joe

DLRdan · Post by **DLRdan** » Wed Jan 21, 2015 5:50 pm

It will undo with the block in place. It is best replaced with a nut spinner/driver if you have one but can be done with a spanner and some careful manouvering.

Joe · Post by **Joe** » Wed Jan 21, 2015 7:10 pm

ok thanks, i will have a look its in tightly at the moment but i think the spring may be bust

Joe · Post by **Joe** » Sun Feb 08, 2015 2:18 pm

Well ive finally sourced the right size washers to give that ago to make the spring tighter, i understand i must place the washer at the end of the spring near the reverser block however im not sure how to get the reverser block apart i have removed it from the loco and have a spanner that fits but do i hold on to the reverser handle and try and move the nut in the opposite direction?

cheers
Joe

DLRdan · Post by **DLRdan** » Sun Feb 08, 2015 3:11 pm

Thats right, you want enough washers so that the bolt doesnt come through the valve block with no pressure on the spring. That way when you tighten the bolt into the valve you should get a good seal without it being too tight.

Joe · Post by **Joe** » Sun Feb 08, 2015 3:13 pm

ok thanks, it is a it hard to get the nut to move while holding the reverser handle but i will give it ago, in worst case i will just get a roy wood reverser

DLRdan · Post by **DLRdan** » Sun Feb 08, 2015 3:15 pm

It should undo but will probably let go very quickly when it does.

Joe · Post by **Joe** » Sun Feb 08, 2015 3:18 pm

Yep just gave it a good tug and now I've got it apart , one thing I notice is that on the block with the 4 Holes the top and bottom ones appear to be blocked , is that normal ?

Joe · Post by **Joe** » Sun Feb 08, 2015 3:25 pm

Right I've put 2 washers on and it feels firmer to I will give it a go

DLRdan · Post by **DLRdan** » Sun Feb 08, 2015 3:29 pm

The top and bottom ones will be as these are only for the bolts and long as the inner pair are clear its fine.

Joe · Post by **Joe** » Sun Feb 08, 2015 5:55 pm

Well i just test steamed it and it was lurching forward but then the wheels locked which suggests the cyinders stopped sliding, any ideas why?

DLRdan · Post by **DLRdan** » Sun Feb 08, 2015 5:58 pm

Possibly water in the cylinders. If you turn the wheel by hand while gently pulling the cylinder away from the frame it should come out

Joe · Post by **Joe** » Sun Feb 08, 2015 6:04 pm

ok thanks i will give it ago, your advice is really appreciated thankyou very much

Joe · Post by **Joe** » Sun Feb 08, 2015 6:13 pm

ive just noticed one of the screws that holds the cylinder to the reverser block isnt screwed in properly after i took it out so that may explain it?

Joe · Post by **Joe** » Tue Feb 10, 2015 12:42 pm

Well after sorting the screws and adding washers tot he spring ive given it a steam up on the blocks and it seems to be much better and produces a much better sound, i also tested it on a short section of 0 gauge track (not long at all) and it seemed to run fine but i will have to wait untill i take it to a running day at my local group to see if it will run ok on rails as i think it is still leaking a little steam from the cylinders. May need new O rings, is this a difficult job?

cheers
Joe

DLRdan · Post by **DLRdan** » Tue Feb 10, 2015 1:22 pm

The cylinders you have fitted aren't fitted with O rings. Most mamod type locos have a bit of steam hanging about the cylinders so I wouldn't worry.

Joe · Post by **Joe** » Tue Feb 10, 2015 1:24 pm

Ok thanks , I will post on my progress in the weekend When I will run it properly, it does seem to be leaking more than some on vids on YouTube but it might just be the cold weather

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Steam leak from reverser block

Steam leak from reverser block

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