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Preview Video

Now things have settled down a little and Vintage Tractor Engineer has found a moment, we’ve produced a short preview video so people can get a feel of the content.

Here it is, enjoy…

The TE20 in question will only lift a small weight on the rear linkage, and then only when the engine is running at high revs.  Patrick has inspected the pump components and (with the help of the DVD) concluded that everything is in reasonable condition.  However, he did notice that there were neither o’rings or gaskets fitted between the pump body and the valve blocks (as shown in the film).

This is likely to be the cause of the lack of pressure in the system.  Also Patrick should take a look at where the lift cylinder joins the top cover, as there should also be gaskets at this point.

Here is what Patrick says…

Hi Steve,

Many thanks for the T20 Hydraulics Video – Very well put together. I bought it because my T20 hydraulics are under-performing. I wonder if you might be able to give me a bit of advice?

It was restored and rebuilt by the students at Bicton Agricultural College as part of their engineering course. It is pretty much in excellent condition, but the links will not lift anything much above the weight of a man (not my cutter bar mover for example), and even then only if the engine is at full revs. As soon as the revs drop or the engine is switched off, the links start to fall. I have had a good look through, pulled the pump out and most things seem to be in good nick. No movement on the bushes etc. The one thing that I did notice is that, although the pump has an oscillator fork, there is no oscillator drive strip…. I think it is otherwise an old style pump – it has the old style combined relief valve and does not have spaces for o rings on the valve chambers suggesting it is the gasket type. Would the lack of an oscillator drive strip cause any real problems apart from making it more likely that the control valve will stick? The relief valve looks like it is in good shape, and so I am not sure that is the cause of the links dropping…. The only thing I can see that might be causing it is the fact that they didn’t put any gaskets between the valve chambers and the body of the pump. As it doesn’t have o rings (or space for them) either, would this be enough to let the linkage drop?

Cheers

Patrick

Patrick got back to us the next week to say…

Steve, you’re right. it is missing the gaskets between the top cover and lift cylinder too…. I’ll get a new set.

As I said previously, the oil was all contaminated with water and looked a sickly orange colour.  There was also about half an inch of dirt and deposits in the bottom of the transmission casting.  Either this dirt or the moisture in the oil was the probable cause of the control valve been seized in one position.  The control valve oscilating rod had also become detached from the control valve.  We don’t know if the cause of this was the stuck control valve or if the detached oscilating rod was the cause of the stuck control valve.  What matters is that it was relatively easy to free off the control valve.

side pates and hydraulic top cover removed

The pistons of the hydraulic pump were scored from the dirt in the system (there isn’t a filter on the TE20’s so that probably didn’t help this situation), but the vavles and everything else seemed OK.  Although the control valve had been stuck it was in remarkably good condition and still a good fit in its body.  However, it is very difficult to assess the fit of the control valve as only the slightest bit of wear can cause problems.

We would normally have used a repair kit on this pump to bring it back to optimal performance, but the owner of the tractor simply wanted the control valve unseizing.  So on the video we just went through how to remove and strip down the pump and then how to rebuild it.  We also looked at the vavles, lift cylinder and cross shaft.  The pump went back together using the existing components and then we tested it out.  Everything worked just fine and in fact we left the cultivator in the raised position over night (with engine stopped) and the next day it was still right at the top of the lift, just where we had left it.

We put a pressure gauge onto the system and tested when the oil was warm.  It read 2000 psi.  The rated pressure is 2500 psi, so this did show that the scores in the pistons were causing a less than optimal pressure output.  This didn’t really matter, as it showed the consequences of refitting the slightly worn pump components.  The point of the DVD was to show how to strip, assess and rebuild the pump and other components of the system – which we were able to do.

the pto shaft needs to be pulled to remove the hydraulic pump

The concept of our DVD’s is that if an untrained person watches them then they will be able to do the maintenance task on their own tractor.  I think we have achieved this again with this DVD.

Now take a look at the colour of the transmission oil that came out.

The oil clearly hadn’t been changed for years and water had emulsified with the oil to make this yellow creamy fluid.  There was also half an inch of corroded aluminium deposits and dirt in the bottom of the oil reservoir.

The mixture of oil and water is caused by condensation forming in the transmission housing and then dripping into the oil reservoir and mixing with the oil.  This is the reason for regularly changing the oil even if the tractor isn’t been used for many hours a year (like many Fergusons that are owned by enthusiasts).  In fact the less the tractor is used, there is an argument for changing the oil even more often (due to the increased likelihood of condensation forming).

A few weeks ago one of our customers rang to say he had a TEF and the hydraulics weren’t working.  Could we go along and take a look.  So we did and after a quick initial assessment decided it was going to need a full strip-down of the hydraulics.  The next day we went back armed with a tool box and the video camera.  And that was it, the TE 20 Hydraulics DVD was now been filmed.

What about our TEF with the seized engine?  Well it’s still there and we intend to get to it as soon as we can, although we’ve got Joe’s TVO35 to work on first – it has a frosted block so Joe has found a second hand block to swap over.

In the mean time, the Hydraulics DVD is to finnish off which will take me a few weeks to edit all the footage and author the DVD onto disc.