GT-14 no brakes?

[FatJackDurham 318]

Hello, I just got a 1972 GT-14 is pretty good shape, a little sluggish, but the transmission seems to work well forwards and back. 

 

But, when I push the brake pedal, suddenly I am in free fall. It pops the transmission lever into neutral and the tractor rolls freely until I take my foot off the pedal and grab the lever and put it in reverse.

 

Is this the normal behavior? I know the seventies were weird, and a garden tractor with a cigar lighter is pretty tight, but stopping is kind of a thing with me, so I'd appreciate some insight.

 

I am the third owner of this beastie, and it came with all the original brochures and manuals. The owner's guide only says the brake and parking brake work in connection with the automatic transmission. So, I am wondering if I am missing a connection or linkage, or worse, that there is something broken. I traded a Winchester 92 for this tractor and am as excited to finally own a Wheelhorse as I was to finally own a winchester... so anyway, there it is. Thoughts?

[953 nut 55,809]

    The brakes on the GT-14 consist of dynamic braking of the transmission and a parking brake which is probably chewed up by now. The attached Sundstrand manual has an adjustment procedure in it. As for the sluggish operation, the first thing to do is change out the fluid ( ATF if it is red, 10W30 if amber) and replace the filter with a NAPA 1410. This may be all that is needed.

Sunstrand Hydro (part 1).pdf

Sunstrand Hydro (part 2).pdf

Sunstrand Hydro (part 3).pdf

Sunstrand Hydro (part 4).pdf 

Let us know how you come out.

[Walt 339]

[FatJackDurham 318]

Thank you! The sluggish isn't the tranny, it's the engine. Needs carbs cleaned. I'll examine you attachments!

[SylvanLakeWH 25,957]

[KC9KAS 4,741]

[meadowfield 2,595]

If it's set up properly then it will lock the wheels when you hit the brakes, it will then roll slowly as the fluid escapes.

 

dont ever pull the handbrake rolling, it will chew whatever is left of the transmission brake pawl

[FatJackDurham 318]

I found this post, now, that shows the pawl. So, I gather for the parking brake, the pawl drops into a gear tooth to hold the wheels steady, correct? And they get destroyed over time by people dropping it into the gears/internal milling head while the vehicle is still moving.

 

But, that doesn't help me understand how the brake works. I have seen some animations that suggest in hydrostatic trannies, that by just putting the gear in neutral, instead of forward and reverse, the hydraulic action itself is the brake. But I don't know if the same applies here.

 

ANyway, I'll take a gander at the parking brake setup and see if I can adjust that in till it bites.

 

 

 

 

[pfrederi 17,885]

You are correct it is the hydro unit itself that provides the "braking" .  Problem is as the hydro wears (allowing leak by) braking becomes less powerful.  Later hydros Wheel horse added a physical band brake.

Edited October 24, 2016 by pfrederi

[FatJackDurham 318]

33 minutes ago, pfrederi said:

You are correct it is the hydro unit itself that provides the "braking" .  Problem is as the hydro wears (allowing leak by) braking becomes less powerful.  Later hydros Wheel horse added a physical band brake.

 

Okay, so two questions pop into my head now:

 

1) Does the wear you mention that can decrease brake efficiency affect the normal operation of the automatic drive, or is the braking feature a different "path" inside the hydro gear unit, that can degrade separately from the transmission? I am asking because the transmission is "spritely" to say the least, and when climbing hills, the engine bogs down, but the transmission doesn't seem to slip at all. So, as a beginner, my instinct is that the drive part of the hydro is working.

 

2) Does the brake pedal have any connection to the transmission other than disengaging the drive lever? Or, is simply moving the drive lever back to neutral EXACTLY the same as hitting the brake pedal?

 

Thanks.

[pfrederi 17,885]

Actually it is pretty much the same hydro system. The engine can makeup for some of the age related weakness.

 

Can you push the tractor at all engine off and the tow valve in drive position?

 

Yes all the brake pedal does is push the control lever to neutral. There are some adjustments you need to check to assure it is moving it to exactly neutral.  I do not have GT14 so I defer to other members and the Owners manual on how to check the adjustment

[FatJackDurham 318]

Okay, great! I will check the pushing with the tow valve, but unless the tow valve is already in the tow position and I didn't know it, I'd say yes, because I pushed it off the trailer with it off. I'll let you know! Thanks for the answers.

[pfrederi 17,885]

If you can push her with the tow valve in the drive position the she is probably a bit tired.

 

[953 nut 55,809]

Make your adjustment to the brake system and then you can give the transaxle the old acid test; chain it to a tree and put it in forward and see if it spins the wheels. then chain the front to the tree and hit it in reverse, same deal. If it is not strong it may need the acceleration springs replaced. Mine was puny and member @refracman hooked me up with a fellow who has some a few years back; big improvement.

[FatJackDurham 318]

Thanks for all the hints.

 

1) I can push it easily with the tow valve in the drive position... 

 

2) I don't now about a tree, but when I was using the plow to push dirt, the engine booted down before the wheels spun, but I had wheel weights, and I weigh 350 so I don't know if that counts.

 

does a bit tired mean I got a bit taken? I tried to find out if the tranny was good when I bought it, but I didn't know enough....

 

what do you suppose my options are?

[953 nut 55,809]

On 10/23/2016 at 8:41 PM, FatJackDurham said:

sluggish isn't the tranny, it's the engine. Needs carbs cleaned

Have you done the carb cleaning yet? I have had good results with Seafoam products, remove the air cleaner and with the engine running at half throttle, spray the aerosol carburetor cleaner in until it begins to die out, once it recovers repeat several times. Also, add Seafoam liquid to the fuel. Hope this helps.

[pfrederi 17,885]

Being able to push it (more than a foot or two) with the valve in drive is not a good thing.  If you are lucky the valve itself may not be seating correctly.  Download the sundstrand manual form here and try removing cleaning and reseating the tow (also called push) valve.

 

http://www.wheelhorseforum.com/files/file/24-transmission-hydro-sundstrand-sm-492-4206pdf/

 

Has the fluid and filter been changed recently??

 

 

[FatJackDurham 318]

Not sure. My plan is to take the tin off this weekend, degrease the sucker and wheel it into my workshop for an extended stay.  You'll be hearing more from me in the months to come....

[Sarge 3,463]

Those are typical signs of weak direction valve springs in the older style hydrogear - that is common. There are places that have parts available, look up LJ Fluid Power in Michigan - they have a lot in stock. The GT14's had a lot of issues with neglect and abuse due to their size and power - mostly abuse. If you find any model from that era that still has a stout hydrogear - they are amazing when the work correctly. 

 

Sarge