MF175 steering questions

[JBMac]

Good Morning,

I need a little help with a steering rebuild (hydraulic cylinder)on a diesel 175. I"ve read before that everything needs to have no slop in it in, except where necessary. Currently, the thing has almost a third of a turn of the steering wheel before it turns the wheels. It does work very smooth, however once, it starts to assist. Here is what I plan to replace:
1. Lower arm bushing
2. upper arm shims
3. swivel and link assembly
4. cylinder anchor pin
5. valve link retaining pin
6. all internal oil seals and o-rings
7. piston rings are scuffed, replace? has plenty of assistance

I have been able to remove the assist valve linkage end, but my assist valve doesnt have a clip that the manual shows, just a thin, loose fitting washer, that as far as I can tell, is not and e-clip or circlip so I can"t get the rest of the steering booster valve removed.
Also, the end cap on the booster valve shows three small screws holding the end cap on, mine has three rounded pins, almost like a rivet, the seal is disentegrated, so do I go ahead and cut them of with a chisel and replace with screws?

One more thing: One I removed the resevoir on the P.S. pump, there was no filter assembly to be found like both the parts and service manual show. Instead, two female ports, one with a 90 -degree pipe fitting with a crude screen filter and another straight pipe that appears to be a releif valve assembly. Do you think my manuals are for the wrong years? Is this screen filter sufficient? There is some scuffing on the cylinder"s piston which leads me to beleive that it is not receiving sufficient filtering (it was torn slightly, though)

Thanks in advance for any help. Let me know if you all think more parts need to be replaced or less. I"ve tried to use the correct parts names out of the manuals. I really do appreciate any help you all could offer.

John

 

[Anonymous-0]

Hello JB Mac,
I believe that there are several steering systems fitted to the 175 but the principle is very much the same.
The system does not require 'slop', it requires correct adjustment and maintenance to work correctly. Before you start replacing items it is necessary to find out where the wear is present and concentrate on those items. Much of the steering wheel play is likely to be in the steering box. On the right hand side of the box you will find a 3/4" spanner size nut with an adjusting screw in the middle. This should be adjusted so that you are able to turn the wheel freely 'over' the 'high spot' in the straight-ahead position. Next you need to check all of the ball joints and replace any worn ones. Have an assistant move the steering wheel back and forth and observe for any wear movement where the main shaft goes through the axle casting. Replacing the bushes and the shaft is easy but you will need a special in-line reamer to take them to shaft size. They can be bored to rough size in a lathe but you will need a honing tool to finish them in situ. A new anchor pin may provide a partial solution but you will probably need to make up some packing to prevent the end of the cylinder rod lifting when the steering wheel is turned. This lifting can be enough to destroy the power assistance because it lifts the ram instead of opening the spool valve. There must be NO play in the agjustable barrel linkage. Play here will reduce the amount the spool opens.
When the system is assembled with the barrel disconnected screw the tapered pin down until the movement is cancelled and the linkage is locked. Adjust the barrel so that the pins can just be fitted. and lock the nuts. The standard adjustment is to unscrew the tapered pin 7 (seven) turns. Test the steering and you should even, equal power assistance. It may be necessary to carry out further adjustment. Do this in one half turn steps until you have the best results.
DavidP, South Wales

 

[teighs]

Where do you find the special in-line reamer?

 

[JBMac]

David,

Thank you for your help. I have checked the steering box adjustment and drag link, surprisingly, it"s good. Also, the splined shaft that comes through the casting appears very tight. I think that all of the assist valve parts and pins are worn (some openings are almost slightly oval). The cylinder also leaks oil badly, hard to tell where from. Any tips from anybody on part availability is appreciated. I"m a fairly good mechanic, do I let a shop handle this project?