[Shaun_Ashmore]

Anyone know what size coupling a pro mount 25 uses? I know that they are tb woods, I did get a spare but they are expensive even when they are in stock.

Shaun

[Jamie Pearson]

Either a 7J or 8J isnt it?

[Shaun_Ashmore]

From what I can understand from tb woods website it's a 8E epdm

Shaun

[Jamie Pearson]

Last one I supplied for a promount was a J. Spose it depends on age of machine.

[Paul Moss]

Have you gone through the two sets I got you ?

[Shaun_Ashmore]

I've gone through about 3, I've come to the conclusion that I need it on full throttle when cleaning upholstery they wear out so fast when reducing revs.

Looking at tb woods website it looks as though I've had different ones all no.8 but made of different material

http://www.abssac.co.uk/s/SureFlex+shaft+coupling/3/34/

Shaun

[Shaun_Ashmore]

Would these be suitable?

http://www.ebay.com/itm/TB-WOODS-NEOPRENE-SURE-FLEX-COUPLING-SLEEVE-8N-NIB-/310939969045?pt=LH_DefaultDomain_0&hash=item4865776615

Shaun

[Paul Moss]

Just a different design, but the same size coupling. They are not as robust as the older style, that's why I bought them from the states.
Shaun, to go through that many couplings in such a short amount of time can only mean you are not using the machine correctly or there is a problem with it.
And yes it must be run on full revs all the time, reducing the revs on this type of machine will excellorate the wear on your couplings and lots of other parts of the truckmount.

[Shaun_Ashmore]

You are right reducing the revsiss a big no no just has a bit too much suck for upholstery sometimes.

Shaun

[Paul Moss]

Use the vac relief on your cfr tool.

[John Kelly]

You need to ensure that the couplings are perfectly squared up. You need a small metal straight edge and a pair of calipers to do this. Even if is slightly out it will stress the rubber insert and cause premature failure.

[Shaun_Ashmore]

When I put the last one on I scribed areas to re align them I'm pretty sure that they were set in the correct place.

Shaun

[Paul Moss]

I replaced couplings once on my old 20 and also about 18 months ago on my 25. You don't need to be that worried about setting them perfectly square, I just did it by eye on both occassions .
The couplings are that big that they allow for movement, that's why they are rubber 

Shaun the main problem that makes the couplings wear prematurely is not using it on full or nearly full revs and ( this is the biggest problem) the vac relief sticking, you must lube this regularly.
Shaun the maths don't add up with you mate.

[John Kelly]

They are quite a hard rubber and misalignment will cause extra stress. If its an air cooled engine it needs to be run at full revs for the fan to draw in enough air to keep it cool.

[Paul Moss]

Yes John, you are correct they are air cooled.

[Paul Moss]

And no the rubber is soft to allow for movement.
The new couplings are a lot harder and that's why they are shearing. The older style is much softer and takes the stress  that's why I bought I few sets years a go from the states,
Only used one set and still have 3 as spare