SOS Band adjustment warning

jeff pk

Member
I blame only myself for tinkering with something I know so
little about, but it would've been nice to hear a warning from
the boards SOS "experts" that one should never unscrew the
band adjusting screws more than one turn. If you do this, a
strut will drop off the band and it will cost you $2500 to get a
shop to repair it.

Both "manuals" Ford and IT don't think to warn the owner.
Here's what the Ford manual says: " Remove No. 2 band-
adjusting screw as much as possible...Note: No. 2 band must
be completely free and the cover cover removed evenly..."

The IT manual is just as bad.

mooger came closest to warning me about struts dropping,
but he was referring to the servo side of the band---and I'm
and idiot when it comes to these things. With further research
I found a thread where he mentions the band screw/strut
dangers.

Again, I only blame myself. Hopefully this warning will save
some other sap from doing what I did---plus, band #3 seems
like it was messed up already so I was probably in for it
anyway.
 
It should not cost $2500 to repair the damage. Assuming no other parts need to be replaced, it should be not much more than an 8-10 hour job at the most to split the tractor in the rear and disassemble it enough to reach the strut.
 
Jeff pk,I did the same thing.so i took it apart at rearend remove some parts, put fork back in,reinstall parts,new seal and "O"ring adj. bands,everything work ok.
 

In our defense, us "experts" that is, I've never encountered that problem. Therefore, it did not occur to me that one might. Your B2 was not applying for reasons other than the little pin that is the common culprit. That may mean your B2 was not in the shape most are and let the strut drop for that reason.
 
You"re blaming yourself and I certainly don"t wish to make you feel worse, but the real lesson that could be taken is: Don"t drop down in the middle of a technical manual and start twisting bolts -- begin at the beginning.

You stated twice in prior posts that the manuals were "cryptic," but they"re actually straightforward. Both the Ford and I&T FO20 SOS sections begin with a description of how it functions followed by troubleshooting and adjustments. Then begins complete disassembly/overhaul followed by reassembly.

There was no spring pressure against the interlock cover so there was no need of "releasing the Band 2 adjusting screw per manual instructions" as you did. That indicates you were in disassembly/overhaul instead of the adjustment section, and is what I meant by starting in the middle of a technical description. I cautioned twice about losing a strut or struts - "SOL at that point, etc."

As I understand it, there were problems with the transmission when you got the tractor, so somebody may have been there before you. A few years ago, a guy asked here about SOS problems in a tractor he was looking at to buy. The owner told him that he had "yanked out that screw trying to fix it" (as he pointed to a band adjusting screw).
 
Are you saying that there IS some section in these manuals that warns the mechanic not to loosen the band adjusting screws too much, or a strut will drop? If so, I'd like to see that---I must have missed it.

Also, what is "straightforward" for one person might be "cryptic" to another. I'm not well versed in the language or theory behind complex machines. I can tune the older motorcycles or tractors, and have replaced a clutch in an old Volvo once.

It was my impression that my loosening the #2 band screw is what resulted in the lack of spring pressure behind the cover.

Please don't get the notion that I don't value your opinions or help. I know you warned me about struts dropping. and if I had followed your warning to its conclusion I would not have dropped that strut.
 
I guess even the "experts" can learn new things...

A couple of questions:

The little pin is on the servo to #3 band, so how is that
connected to B2 not applying?

Can I safely work on the engine without damaging the SOS
more---keeping the traction lever disengaged? I don't want
that loose strut getting into a moving part...

Thanks for the input...
 

The little pin connects a sequencing or timing valve to servo 3. This valve works with servo 3 to keep B2 from applying simultaneously with B3. If the pin is broken or gone the valve stays in position where B2 thinks B3 is still applied.

You can do anything you want to the engine and it will not hurt the SOS . . . unless you run it without oil in the SOS.
 

So, if it's acting like the sequencing valve is broken, but it's not, what else could be causing that action?
 
I already answered that question once.

"Re: Technically challenged SOS repair in reply to jeff pk, 04-16-2013 16:03:36

I've forgotten - why did we suggest this pin to begin with? Are you missing 5,6,7 & 8? If so remind us which tractor you have again. If this is the scenario, B2 is failing to apply for some reason. The little pin is the most common culprit. Since this is a spring applied band, one would guess a sticking B2 valve keeping hydraulic pressure applied as the next most likely cause. Either that or the band is shot, broken or not adjusted properly.

Since you believe you've dropped a strut anyway, you'll likely get the chance to look the innards over well. Check it all out. Let us know what you find."
 
jeff pk wrote:

"Are you saying that there IS some section in these manuals that warns the mechanic not to loosen the band adjusting screws too much, or a strut will drop? If so, I'd like to see that---I must have missed it."

Ya got me there. There're no warnings because none are needed. The manual deals with the band adjusting screws twice:

First, it tells how to adjust the bands. Follow the instructions and there's no possibility of error.

Second, in the overhaul section, it says to remove the screws (by screwing them down into the case). At that point, the photos show the trans sitting on a stand with half the parts removed on the way to a empty case (bereft of struts plus everything else).
 
No warning needed? On this thread alone there are two people who did it; and for some reason you yourself thought to warn another poster on this site in another thread about doing it.

From Oct.2011
"The B2 and B3 servo springs push against the interlock cover so before unbolting the interlock, the B2 and B3 adjusting screws have to be backed out to relieve some of the spring pressure. The risk there is that the band actuating struts will fall out of place if the adjusting screws are backed out too far. Each strut is a small, approximately square part that's the final bit of linkage between servo and brake band. The struts aren't pinned or held in any way - they're loose. Servo spring pressure keeps them in place. There's no access to replace a strut without taking the trans apart."
 

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