Thread: Hi-Finish Aluminium Grinding (Hydro-Drive Refurbish)

Hi DarBee,

Welcome,
Looks great to me but I dont really know what I am looking at. You wouldnt have some before shots would you?(or its the horizontal face in the first picture what the vertical face looked like before you went to work on it?)

Could you add brass/steel shim between the alum and steel to either
1. cut down on the wear or
2. or the wear to the slim so at least it will be quick and easy to replace next time?


Stuart

G'day Stuart,

The machined face is on the pump side of the housing. The other face (in good condition) is the motor face. The rotating cylinders are those with the 5 piston ports. I have only refinished the pump face of the cylinder and housing.

I have discussed the idea of fitting a very thin steel shim to the Al face/s. I envisaged it would be 'tagged' about 3 times around the perimeter. The shim would need to very thin <.005" I would think, so as to try and guarantee that it will lie flat enough against the Al face to be leak proof. The problem then is how to cut the shaft hole and 2 x arc-ports into the shim without any distortion. Likely a fairly simple job if one had an EDM machine or access to one.

I suppose this thread has exposed the ability to recover worn hydro-drives (to a limited extent) as well as show that the Al faces can be ground with care.

Regards, Daryl

Hi Daryl,

Good work! I must admit, similar to Stu I don't really know what I'm looking at but you have explained probably as best you can. I find this interesting in more ways than one as I also have a ride on mower that uses the hydro drive (hydro gear) similar to the one you have re-conned. My mower has about 60 hours on it so I'm not excited by the prospect that it's already nearly 1/3 way through it's life! I guess time will tell.

Nice to know that with time, care a patience, you can repair it.

Thanks for sharing.

Simon

Thanks Simon, moving slightly off the topic a bit, the most common hydro drive Tx's used by various brand ride-ons are made by TuffTorq - their web pages contain many many models of Tx's and with some degree of navigation skills, you can find an illustradted parts breakdown for all of them. The parts are generally easy to get, but are over priced in Oz - annoying really when the $ is better than parity. My original Tx was a TT K-46 (rated about 150 ftlb torque), it lasted just 200 hrs of HARD work. I imported a larger Tx (K-66) rated at near 300 ftlb torque - fitted well after some 'product improvement' mods. It also has lasted 200 hrs, but VERY HARD work. After my 1st attempt to recover the pump/motor assy failed, I put in a new pump/motor kit. That then gave me the time to consider another (grinding) approach to the rework.

Don't be put off by the complexity of these drives, they are really pretty simple and the only high tolerance items in the whole Tx is the pump/motor assy (shown in the pix) and the swash plate bearings that control the rotating pistons.

Regards, Daryl

Thanks Daryl,

I've got a Husqvarna with 60 Hrs on it so I'll have some time to ponder such re-builds! Are you telling me you have a ride on with more than 400 hrs of hard use on it?!!!!!!! Wow! It still a good unit when you think of all the other components that can wear out! If I get that from the husky I will be over the moon even if I have to rebuilt the hydro drive!

On another note, I had considered changing the pulley size. 7.5Km/h top speed can be a bit boring! I'm not sure if the pump is maxed out already and changing RPM of the hydo pump would make any difference but with 18 horses under the bonnet it should be able to do twice that!

Then again, one thing would lead to another and i would then feel complelled to compete in something like this:

Mower Racing Australia - YouTube

Cheers,

Simon

Hi Simon,
In my view, better to tickle the governor up a bit on the engine; that way you will also get a corresponding RPM increase of the cutting blades. If the road speed is too high for the cutters, the grass will start to look choppy.

My 'mower/tractor' is a John Deere 110 17.5hp. Its about 8yo. It took 6yrs (& 200hrs) to wear out the original Tx & just 18 months (& another 200hrs) to wear out the upgraded one. To be fair, I also added pretty serious quad bike tyres to the rear and a bucket on the front and a very heavy push-bar when not using the bucket. So far I have only rolled it 4 or 5 times!! But I'm not as skilled as my cousin from Seymour (a professional big-rig driver) - he has only rolled it once! Our lot here is very steep - which is why I need a lot of weight on the front wheels. The rear tyres are also full of water about 20kg each - ah, then there is the 50L spray tank on the back as well.

A current WIP project is to add a hydraulic ram to the bucket and push-bar.

The mower racing is cool - but I suspect if it came to a pull-off, I could do it at 1/2 throttle. Regards, Daryl

Hi Daryl,
With brass you could bolt it between two pieces on MDF and mill the holes you need, that should work ok.
Not so sure about steel shim, it might be a little hard? If HHS wont do it carbide should(though I havent tried it).

Wouldn't steel on brass be better than steel on steel anyway?

Stuart

Aaaahhh - Stuart, now you have given me job already - I'll have to hunt down some brass shim to tomorrow now!

I might try 3x small roll pins to tie the perimeter down rather than trying to machine peripheral tabs. Thanks for the great tip - a memory jogger really. I'll post a pic of the process and result - maybe by the end of the week if I'm allowed out!
Daryl

Hi Daryl,
Whilst i don't own a ride on, the thought of grinding on the mill is a new one. I would not have thought that the top RPM ofthe machine would have been nearly fast enough, especially with a small dia wheel.

I saw a mower race once, as a prelude to an oval dirt track race of some sort (my mum was dating a rev head at the time, not really my thing). The funniest 2 things to see was a: a mower rolling it on a corner...maybe with some help from another, and B: someones throttle linkage coming undone and them finishing the race bent over the motor and working the throttle with one hand.....