Stihl ht75 polesaw shaft problem

[Jack.J]

Hi everyone,

First post on here in a fair while.

I have a stihl ht75 that had a bent extendable tube. I ordered a new one, took the pole saw apart and when putting back together with new tube it's like there's parts missing as it does not drive the head. All parts that came out of it are here but when looking at the diagram on l&s it seems there should be more, so I'm at a bit of a loss and also wondering how it was working before this. 

I've searched on here and google/ youtube without much luck so posting hoping that someone knows, Attached some photos of the bits I've got aswell as the l&s diagram 

All help greatly relieved 

Cheers

Jack

[pleasant]

These are an absolute nightmare to 'rebuild' Years ago we attempted to rebuild a few, but they never assembled how they come from the factory very well and we ended up taking them apart several times to get it sort of right, but were never happy with them. For example, you would extend the head, but then the inner drive shaft wouldn't extend with it, so you lost drive and all sorts of other things. In the end as it was our name on the repair, we just ordered a completely assembled shaft inner and outer then just reattached the engine on one end and the pruner or hedge cutter head on the other.....saved a fortune in labour for the customer even thought the fully assembled drive tube was dearer, and we could guarantee it would work.

Edited Sunday at 20:05 by pleasant

[spudulike]

When I was in the game, I appeared to be the only guy in the area that could rebuild these things. It started with one that I took apart in my garage with a mallet and bits shot everywhere so I had to sort out what every bit did and where it went.

Once I had done that, it was relatively easy.

You are missing one of those funny sliding bearings, you should have two with the splined internals and one with just a round inner. You also appear to be missing the round tube cover that sits on that splined shaft which is a bit baffling as it slides up the round slider bearing you have pictured.

These are an acquired taste to rebuild but once you have done a few, it becomes much easier.

Oh...you are also missing the fecking great springs that usually sit between the sliding bearings.

It has been a while since I last did one.

[Mark_Skyland]

1 hour ago, spudulike said:

When I was in the game, I appeared to be the only guy in the area that could rebuild these things. It started with one that I took apart in my garage with a mallet and bits shot everywhere so I had to sort out what every bit did and where it went.

Once I had done that, it was relatively easy.

You are missing one of those funny sliding bearings, you should have two with the splined internals and one with just a round inner. You also appear to be missing the round tube cover that sits on that splined shaft which is a bit baffling as it slides up the round slider bearing you have pictured.

These are an acquired taste to rebuild but once you have done a few, it becomes much easier.

Oh...you are also missing the fecking great springs that usually sit between the sliding bearings.

It has been a while since I last did one.

You're a better man than me.

I've always struggled to rebuild these things. I did one a month or so ago and I've got another one to try and sort out this week. Half of the problem is that the bearings break down so a lot of the parts have moved and arent in the right place.

There is a good video on you tube somewhere, ill try and dig it our for the OP. 

You need to make sure that you have the right bearings as there are two types, they are installed the correct way, the springs are installed correctly and that you have the splined shaft installed correctly as it has a circlip that makes sure it moves when you extend the pole. IIRC!

I think one of the issues is that the stihl diagrams are misleading and they don't show how its properly put together.

Ill try to take some photos when I put the next one back together.

 

 

[spudulike]

Yes, all sounds about right. Generally those slider bearings fall apart from lack of grease and implode. There is a C clip that can come off and stop the drive, failure of the "non splined" bearing can stop the drive to the head plus one of those bearings is riveted to the shaft and failure of the rivet can cause lack of drive.

Agree that the Stihl diagram is pretty confusing but if you look at it enough with the parts in front of you, it does make sense.

The bearings have slots in them to ensure they locate in the large outer shaft correctly....yet another hoop to jump through.