135 Power Steering Explosion

[Dirtleg]

Today while bush hogging around my place the hydraulic valve on my power steering started gushing fluid. At the same instant my steering wheel got loose and the retaining nut came off. I still have mechanical steering albeit with a wobbly steering wheel.

My thought is that the retaining nut let go allowing the steering shaft to drop down into the column and perhaps unsealing (due to a narrower section of the steering shaft) the hydraulic valve. The nut will not go back on as the shaft now seems too short.

What are the chances that if I were to pull up on the steering shaft and get the retaining nut back on and tight that this will solve my problem. If the steering valve (hydraulic) needs to be repaired what else should be done while I am in there?

Thanks for any advice.

 

[Dirtleg]

Update. Never mind what my thoughts were about what happened. What really happened was this. There is a small lip seal down inside the steering shaft support/cover assembly. It let go and the fluid built up pressure behind the steering shaft bushing. Now the nut that holds the steering wheel on must have just been barely hanging in there. Once enough pressure had built up behind the bushing the nut let go and the whole assembly came loose. Also unleashing the fluid that had been trapped behind the bushing all at once. That is why it shot out so badly. The bushing was also pushed up making it seem that the steering shaft was too short.

I got the parts from the Massey dealer today and ordered a factory shop manual. Also got new oil pan gaskets while I was there. Hopefully once I have a chance to work on it again it will be leak free. Wish me luck.

 

[chh]

Loosing your power steering while brushhogging is bad enough. I'd sure had to have the steering wheel pop off.
Good luck on getting it all back together.

 

[studor]

Just be carefull to "time" the steering box if you take it apart -- otherwise you will crack the top plate -- instructions on Big Deans CD and in the repair manual -- good luck.

 

[Dirtleg]

Well I got it all back together minus the nut the holds the steering wheel on. I had ordered it from Massey just to save myself some running around but what they sent me was the 13/16 inside diameter nut that goes on the steering shaft just elow the lip seal. I tried to explain this to them but all they could say was that it's what is shown on their database and they could be of no further assistance.

Anyway it looked like a 5/8" -18 thread to me and so on my way home from work today I stopped at the hardware store and picked one up. Well it doesn't fit. It's so close it's driving me crazy but after over 30 minutes of trying to start one nut I just had to accept that it's not the right nut. Both the steering shaft and nut are 18 pitch. I checked them but the shaft is just a little, and I mean too close to see the difference, bit too large.

So does anyone know what size this is supposed to be? Is it a British standard thread. None of my metric thread gauges match the pitch so that's not the problem.

I need to mow at least 2-3 hours a week to maintain things around here and am now a week behind as Sunday was my mowing day last week.

And just to get the background straight I have done industrial maintenance and plant design for the last 15 years so I've had my hands on literally thousands of nuts and bolts. I'm usually spot on with sizing but this one is throwing me off. If it is indeed supposed to be a 5/8-18 thread than I'll need to get a die as the shaft must have had an issue somewhere along the way. That would explain why the original nut was messed up in the first place.

Well thanks for the help and advice so far. Fortunately I didn't have to disassemble the steering box. I only had to remove the shaft assembly cover so the timing was not disturbed.

 

[studor]

Is yours a U.K 135? Otherwise my Detroit one has a domed chrome nut to hold on the wheel -- I got a replacement just last year from the dealer -- looks better than a standard nut as well

 

[Dirtleg]

Well I was over visiting family the other night and my wifes uncle gave me a 5/8-18 die to clean the threads with. It's definitely the right size but the nut would still not fit. Must just be an off spec nut. Strange. So I went and got another one and it fits fine. I will be running it today.

 

[Dirtleg]

Well I drove the tractor for about 1 1/2 hours and then it had the same problem again. I had flushed the system with fresh fluid in case there was water contamination causing it to build excess pressure.

So it must be a failure in the hydrauilic steering valve assembly allowing the full line pressure to reach that seal on the steering shaft which is obviously not designed for any great pressure.

My shop manual should be in on Monday so I'll wait for it before I tear into it again. Anyone have any thoughts as to what has failed in the system?

I noticed it seems that over time there has been a small amout of varnish build up on the parts I have taken off. It peels off as a film so I'm thinking I might as well just do a full system rebuild as if this stuff is getting loose in the system and randomly plugging things up I'll be chasing this for a while.