Sundstrand - parking Brake Lever noise

[Rayp 15]

I have kept the Push Valve on my C 160 Automatic open during my rebuild so I can move the tractor by pushing it.  It has always moved quietly.  However, after connecting the spring to the Parking Brake Lever the Transmission makes a slight clicking noise when the Tractor is pushed.  The tractor does not have a belt on at present so I do not know if this would eliminate the noise, but my question is what is causing the clicking and how can I eliminate it? 

[meadowfield 2,595]

does your transmission have an external brake drum or internal parking brake pawl?   if it's the pawl, then once worn they just ratchet over the gear when the parking brake is set

[Rayp 15]

Hi Meadowfield,

Thanks for your reply to my post.  My transmission does not have an external brake drum and I do not know what a 'pawl' is, but according to my Parts Manual there a pawl behind the Brake Lever.  The pawl in my transmission is almost certainly worn (after 40 years use) but the clicking noise is apparent whether or not the brake is engaged or disengaged and disappears completely when the spring is disconnected (all with the Push Valve open) 

[meadowfield 2,595]

if you are certain the pawl isn't ratcheting, then is sounds like the noise is probably because of wear. I'm assuming by the age it will be a sundstrand piston/piston and the noise can only be the pistons rattling on the thrust plate. Unless of course there is something really loose inside...

[Sarge 3,463]

. I'd suspect once it's been down for awhile the oil will leak back out of the pump into the trans case - you're probably hearing the slippers as each hits the thrust plate . I wouldn't push it around much more like that - if they don't have enough oil to make noise they can score themselves and the plate if they are dry enough without a good film of oil .

 

Sarge

[pfrederi 17,893]

The belt somewhat limits the range of motion for the brake arm.  Put a belt on it and see if your clicking noise goes away.  Seems to me last time i had one apart if you pushed eh brake lever to the extreme off position it started clicking (no idea what it was hitting but after I put the belt on it didn't do it.).  The belt keeps the lever from moving that far.

[Rayp 15]

Hi Sarge,

The Transmission has stood for some two years so, as you suggest, the oil will have 'settled in the bottom. I will try not to move it until I can 'fire it up'!

[Rayp 15]

Hi Pfreder,

Thanks for your reply and suggestion.  I am currently awaiting a belt and will try it with fingers crossed when it arrives.

Hi again Meadowfield,

The noise does sound exactly like a ratchet so will hopefully be the pawl ratcheting.  I must confess I don't understand the function of the Pawl nor why it should ratchet.  I have not touched the transmission as it was working fine before I dismantled the Tractor.  

[pfrederi 17,893]

These are parking pawls.  one on left is what happens when it is used to stop the tractor, grinding itself down on the gear it engages.  On the right is one I repaired

[Rayp 15]

Hi again Paul,

 

Thank you for the photo - I can see now the reason for the warning not to stop a tractor with the parking brake.

[meadowfield 2,595]

There is a thread on my GT14 where I show the pawl and the repair. It really was a rubbish system!!!

[Rayp 15]

Meadowfield,

Thanks for your help and the information - I'm learning a bit more every day, but its a slow process as I am not very mechanically minded. Can I ask another obvious question - where will I find the thread on your GT 14 ?