MadModder

So having fitted the rebuild kit to the RMS100 remote valve unit did it work - well yes on the bench and NO on the machine  Still the 'pop up valve' wasn't sealing - it would start to lift then not be held up by the pot pressure.

This was getting silly - so as there was some slight damage to the bore of the air slide on the original valve, as despite being convinced that it was so slight as not to affect things I decided to push the boat out and buy a replacement unit. The original had let me down once before mid-job, I'd at least get to a known good starting point, and I'd found a slightly cheaper supplier - so I fired the parts cannon !

New valve arrived - body of the valve itself identical but the connection to the silencer was slightly shorter necessitating mounting it forward of the valve itself - not ideal as it's a bit more exposed to knocks in transport. Anyway I fitted it and with great excitement and a bit of trepidation I set up for blasting:

. . . .STILL the pop up valve wasn't seating properly 


Thinking perhaps I had a regulator problem restricting the flow I removed it from the air circuit and ran the blast pot directly off the compressor which anyway regulates to 100 psi - no change !

Rather dispirited I started packing up the kit to crawl away and lick my wounds. As I disconnected the "CF" blast output connector at the base of the machine where the blast hose connects I noticed for the first time that the bronze of the fitting was suspiciously clean and slightly eroded on it's mating surfaces - do we have a leak ? Nothing was apparent in use, and with the noise of the compressor and the air from the blast nozzle I'd not be able to hear anything. The rubber seal seemed fine visually but when I pulled it out it wasn't - it had disintegrated - is this our culprit?

I already HAD a bag of about a dozen spare seals so I replaced it. OK things are starting to get better. The pop up valve now raises with a good solid thump and sometimes seals properly but not every time. However if I wiggle the pop up valve a bit with my finger it seals every time

Now to replace the pop up valve requires the vertical pipe that it is located on to be removed. This had taken some effort as the threads were locked with sealant, and I'd put it back unsealed. Was it therefore screwed further into the elbow that supports it, holding the mushroom lower and hence further away from the sealing ring. Well as an experiment I wound the pipe thread with several wraps of gas rated PTFE tape - (this is much thicker than the usual type) and refitted the pipe with only the first few threads engaged.

So did this make any difference? YES we are seating every time. I don't want to leave it like this as if that PTFE tape gets blown through the system things will clog up.


Now closely examining the alignment of the elbow fitting and eyeballing it to the big rubber sealing ring I am far from convinced that it is pointing concentrically and vertical, but as it's all inside the blast pot and access is only through the 'mud hole door' measurement is far from easy.

I did find a longer piece of 1-1/4" BSP pipe threaded at one end that I screwed into the elbow letting it protrude out of the top of the pot (no popup valve ) to try and measure concentricity and verticallity but then I realised that the pipe thread was somewhat drunken and the tip of the pipe was describing a circle as I screwed it in - no use for measurements 

I'll see if I can turn up a more precise test piece and in the mean time a friend on another forum who has exactly the same pot is measuring the static height of the popup valve for comparison.

BUT we can blast ! I did a test on my 45 gallon incinerator drum and performance was good.

Hi guys, I want to do this too, and I'm wondering what you've done here. For you to understand me better, I would also like to make pedals for my guitar myself. I hope it's not as difficult as it looks in your pictures. I would be glad if someone would write to me and talk in more detail about where to start, which materials are better to choose, and so on. I hope that someone will be interested in talking about it here. I've seen a lot of different accessories on the Internet and even found a website where I've already ordered a guitar tuning knobs, but I don't quite understand where to start my work. So I'm counting on you guys.


(edited by a mod to remove potential spam link)

I'm happy to report that the job is all done & the right hand knuckles seem sound, so no need to repeat the torture for the other wheel for the forseeable future
Seals came yesterday so started the refit this morning. The U/J joints were quite difficult & needed quite a bit of tapping to free off the circlips, which came out easily enough, but two of the bearing cups needed a reasonable force on the press to shift. There is a large 90mm circlip that holds the driveshaft into the axle. Removal was quite tricky due to lack of access, & replacement was also a fiddle having to hold a powerful circlip closed whilst working blind with a screwdriver in the other hand, it took an oath or two but got there in the end.
Actually replacing the taper rollers & refitting the bottom & top pegs was a breeze, though fairly greasy! I'd bought several new shims so set up was no trouble either.
Tractor feels like new now, though the steering assist ram is leaking, so resealing that will be next, though that'll be mostly bench work to be done on a rainy day.
I found a few similar jobs on Youtube  on JD 6000 series tractors & a few on JCB 3cx s too, but nothing specific for the Zetor- however the principles are the same & everyone seems to have the same struggles as Andrew & me with the removal of the top & bottom pegs.

SNIP - nothing worse than a tarted up bit of plant that's '10 yards pretty' - SNIP

Someone whose YouTube video I was watching recently used the expression 'Dulux overhaul'!

(I previously thought 'Dulux' was an ICI brand-name - I didn't realise it was known in the USA as well as in the UK.)

But still, as the famous quote has it: 'Fog in channel - Continent isolated'.          

Just the rams and arms to paint now, Andrew