Lost hydraulic drive

[spicemouse]

1 hour ago, Tracy D'arth said:

Most of the hydraulic drives I have seen use a rubber cushion coupling element, when they shear they don't make a noise.

I think I can support the unit with straps and open it up here with the six bolts.

 

Will this give me the access to the drive plate I need to see if that's what's up? I'll have a few cm of moments in the rubber connections of the water coolant pipes to look in. 

Edited June 3, 2022 by spicemouse

[Tony Brooks]

26 minutes ago, spicemouse said:

That sounds a bit scary! I might be able to move it back a few cm to get a look

 

Plenty of engines used to have a hole in the flywheel housing to expose the timing marks on the flywheel, so I would have no compunction about cutting the hole, especially as the casting is probably aluminium rather than iron. I suspect it may need a mains drill to spin a 1" hole saw but take it easy and keep lubricating  the saw.

3 minutes ago, spicemouse said:

I think I can support the unit with straps and open it up here with the six bolts.

 

Will this give me the access to the drive plate I need to see if that's what's up? I'll have a few cm of moments in the rubber connections of the water coolant pipes to look in. 

 

I would hope so, because the engine feet are on the red bit so you would want to avoid taking that off if you can. Much depends upon the dimensions of the drive and the hole in the red part.

[spicemouse]

I've managed to pull the unit back about 1cm (it's still on it's bolts). I can see in to what I first thought might be some shearing, but maybe more likely just wear. 

The set-up seems to be a central core with three lugs of some kind coming from the unit. These are what look like they had sheared from the plate on the engine. 

 

You can see the best photos I've taken:

 

1

 

2

3

 

 

Am I looking at the drive plate here? Is this what you'd expect? 

 

[Tony Brooks]

I am not familiar with what I can see but what looks like swarf from plastic makes me think something has failed, and one half has kept turning. There also seems to be at least one piece of bent metal in there that I don't recognize as being normal.

[BEngo]

Looks moderately "orrible.  I can see lots of rubber dust and àtorn fibre reinforced rubber, in 1 and 3, and there seems to be plenty of rubber crumb swarf on the blue thing, best seen  in 2.

Best have the box off then you can investigate properly.  If the drive plate has failed, you need to know it is not because it was overloaded by a pump fault.

 I would also be inclined to modify the pipework to the cooler to make it simpler to remove.

 

N

[MtB]

Now you've opened up a gap to look through, try turning the engine with a spanner on the crankshaft nut while someone looks down the gap with a torch. You will probably be able to see/confirm that something is going round and something else that should be, isn't. 

[spicemouse]

1 minute ago, MtB said:

someone looks down the gap with a torch

It's just me here sadly, no pals today..

 

Quite clearly something very wrong here:

 

Currently trying to release the coolant pipes and catch as much as I can, then I'll be able to remove the unit and show you all the money shot. 

[magnetman]

Looks a bit like an HRC or similar "jaw" type coupling. 

Sorry if this has been said already I only skim read it. 

 

 

 

[Tony Brooks]

25 minutes ago, BEngo said:

If the drive plate has failed, you need to know it is not because it was overloaded by a pump fault.

 

Absolutely. We had a few pumps fail when products of cavitation erosion in the pump jammed the rotor. Our systems also did not have filters because the filters kept breaking up and jamming more pumps. Annual running with a pair of temporary inline filters to clean the oil solved that, and then we changed to a more robust type of pump, ability to deal with metal particles wise.

[Bod]

Just an idea.

Start the engine, using a long screwdriver, or metal rod, listen to the pump, then the put the system in gear and listen to both the pump and motor.

Broken engine - pump drive, the pump will be silent.

Broken pump may have some bearing noise.

Broken motor will be silent.

 

Place end of rod firmly against a metal surface, other end of rod against ear, any noise will be transmitted up the rod, so the noise source can be traced.

 

Bod.

[Tracy D'arth]

I posted this earlier.......

 

 

"

I reckon that if you take the water hoses off the heat exchanger, the 3 bolts on either side of the red casting in the angle irons, and the bolts holding the two red castings together, you will be able to pull the whole assembly back without draining the oil.

That will get you to the coupling between the engine and the pump which I would expect to be a rubber cushion drive coupling, and likely sheared."

 

That way the engine remains supported by the angle irons. You will have to remove the rear red casting to get a new drive in anyway.

Edited June 3, 2022 by Tracy D'arth

[spicemouse]

BIG UPDATE:

 

Firstly, thank you all for the various suggestions. I've tried many of them, and there are a few I couldn't try because I'm solo or that seemed tricker than an alternative. I'm now no longer in a position to be running the engine... 

I managed to drain the coolant system without covering everything, and slowly work the unit off. What I found certainly confirms what I thought I could see:

 

 

here is the broken drive section attached to the engine

 

here is the broken section attached to the unit

 

These parts were clearly one part until recently. Given that it looks like it bolts internally onto the engine drive, I assume the blue part in the unit slides out. 

 

Bonus part I found in the engine casing

[MtB]

Excellent progress!

 

SO does the hydraulic pump input rotate or is it jammed solid?

 

[spicemouse]

So it's a TSCHAN coupling (can read the brand off the plate). 

I can't remove this today as I don't have a decent enough allen key:

 

And on the unit:

 

I think it used to look something like this:

 

but now it's missing the rubber and the teeth on the engine side of the coupling. It's likely this coupling hasn't been touched in ~25 years, so maybe just old age?

Next job is to remove the broken couplings, clean up all the waste it's created, and find myself replacements. 

Also, the hydraulic unit turns fine in neutral (which I think is good!). 

[Tracy D'arth]

23 minutes ago, spicemouse said:

So it's a TSCHAN coupling (can read the brand off the plate). 

I can't remove this today as I don't have a decent enough allen key:

 

And on the unit:

 

I think it used to look something like this:

 

but now it's missing the rubber and the teeth on the engine side of the coupling. It's likely this coupling hasn't been touched in ~25 years, so maybe just old age?

Next job is to remove the broken couplings, clean up all the waste it's created, and find myself replacements. 

Also, the hydraulic unit turns fine in neutral (which I think is good!). 

 

 

Now Ringfeder,    https://www.ringfeder.com/tschan/

[BEngo]

23 minutes ago, spicemouse said:

Also, the hydraulic unit turns fine in neutral (which I think is good!). 

Yes, it is good.  Now put it in gear (either way).  It should still turn , albeit with more resistance,  but now the prop should turn too.

 

 In the aircraft world that type  of coupling is called a Layrub coupling, but Td'A has provided a linky.

 

Nà

[spicemouse]

4 minutes ago, Tracy D'arth said:

 

 

Now Ringfeder,    https://www.ringfeder.com/tschan/

 

I'm not surprised after 25 years! 

 

2 minutes ago, BEngo said:

Yes, it is good.  Now put it in gear (either way).  It should still turn , albeit with more resistance,  but now the prop should turn too.

 

I can give this a go tomorrow when i've got someone to watch the prop or do the turny bit. Or turn the prop and watch the other bit. Either way I can't do it alone.  

[Tracy D'arth]

15 minutes ago, BEngo said:

Yes, it is good.  Now put it in gear (either way).  It should still turn , albeit with more resistance,  but now the prop should turn too.

 

 In the aircraft world that type  of coupling is called a Layrub coupling, but Td'A has provided a linky.

 

Nà

I can't find a Layrub that looks like that.  I think its a claw type.

[magnetman]

38 minutes ago, spicemouse said:

 

I'm not surprised after 25 years! 

 

I can give this a go tomorrow when i've got someone to watch the prop or do the turny bit. Or turn the prop and watch the other bit. Either way I can't do it alone.  

You could tie a string round a blade on the propeller and lead it in through the weed hatch then put a weight on it. Then you could see if the prop was turning. 

 

 

[john.k]

The rubber/plastic insert has disappeared ,and the steel/iron parts have then slowly worn away.............must have been making  a terrible racket for years.....run a boat wearing earmuffs...?

[john.k]

Note that hydraulic drives often cant be turned as a gearbox can,due to retained fluid......I think any damage to the pump will be restricted to the drive coupling ,which needs to be replaced ,as does the flywheel coupling and the rubber/plastic insert.............I think the flywheel unit may be problematic,unless its available as a spare.................other wise you will have to fabricate and machine a replacement as a one off.

[adrianh]

Good that you have found the problem! Acorn Industrial are now the UK agents as Ringfeder are German. I have bought from them for some years, anything not standard is usually a long delivery. They have several branches, one specialises in industrial couplings and has the best technical staff.

You will need both the drive and driven hubs and the plastic drive element. Not familiar with this particular spider  coupling but you will either have to accurately specify the bore and keyway details for the driven hub and the locating spigot and drive hole details to order this as a complete item or purchase an unmachined ìtem.

It is usually quicker to get a unmachined set and have it modified locally.

If you find a local electric motor refurbishment company they have the facilities for this and may be your best and quickest approach if you let them source the coupling also. Except a significant bill though.

FYI I am based near Bath 

[spicemouse]

7 hours ago, john.k said:

The rubber/plastic insert has disappeared ,and the steel/iron parts have then slowly worn away.............must have been making  a terrible racket for years.....run a boat wearing earmuffs...?

The engine isn't loud at all, but it's also far away from the driving position, I'm never near it in drive, only neutral. 

Also, it's probably been like this for years, long before I came along.

 

 

Any tips on removing something that's attached in the middle like this? Do I need a special tool? 

Edited June 4, 2022 by spicemouse

[Tony Brooks]

6 minutes ago, spicemouse said:

Any tips on removing something that's attached in the middle like this? Do I need a special tool?

 

Is that on the pump or flywheel.  I find your photos difficult to work out because they often show so little of the surrounding area.

 

I suspect it is on the pump and the pump drive seems to be a splined shaft that has either rusted on or has been chattering so the splines have worn in a manner that prevents them just pulling off. I would inspect the boss in case there is a securing screw in the side, but I doubt there will be. Then try levering while twisting the boss back and forth. The boss seems to have a machining that may be to allow a puller to grip and the puller screw to push against the pump shaft or a distance piece. Only going by what I can see so hopefully someone conversant with these things will be along soon.

[magnetman]

Maybe a slide hammer with a 3 leg puller attachment on it with the claws in the machined groove. 

 

 

Edited June 4, 2022 by magnetman