B7100 will not stop

[sro451]

Good morning, I have a mid 1970's b7100. When i push the clutch in and brakes it stops. However when the brush hog is running on the 3 point hitch I push the clutch and brakes it will not stop it takes approximately 15-20 feet to stop, Unless I pop it out of gear. Very dangerous going down hill. Any answers on how to fix the problem? Thanks Bob.

 

[Piker]

You need an Over Running Clutch (ORC) on your PTO shaft to prevent the rotating mass of the bush hog blades from applying power through the shaft (before they spin to a stop) & driving the tractor ahead. My 1980 B7100 appears to have a built-in ORC (near as I can tell since I don't have a 3 point mower) as it only rotates in one direction when turned by hand with trans. in Neutral & PTO disengaged. Can't find any mention of it in either of the manuals I have for the tractor.

 

[Stumpy]

Yep, everything Piker said. When trying to stop with the PTo engaged your brakes have to dissipate the energy stored in the momentum of the tractor (as usual) and the rotational momentum of whatever implement is attached. The way the PTO shaft is plumbed through these transmissions the implement acts like a second engine attached at the other end of the transmission driving the wheels. The clutch only allows power to flow out of the pto shaft, not back in preventing it from driving the wheels. They're fairly inexpensive but they add length to the PTO shaft so you'll probably need a slightly shorter shaft. Make sure you get the right sizes.

 

[hodge]

Tractor supply carries them. It is a common issue- most older tractors are designed that way, and need an overrun clutch. You have to be REAL CAREFUL without one- the force can push you into places that you don't want to go!
My later model 7100 must have an internal one- when I disengage the pto on mine, I can hear an internal clicking as it stops revolving.

http://tsc.tractorsupply.com/search...icUrl=http://www.tractorsupply.com/-027114899

I don't know if this is the size you need- just showing what it is.

 

[sro451]

Thanks guys that helps. I bought this tractor from my boss, it came with the brush hog, rake and scraper blade for $1000.00 he said he coulded get it stopped and had no use for it. His lost my gain. Thanks again i should beable to fix it for looks like under $100.00 Bob Kohl.

 

[hodge]

Thanks guys that helps. I bought this tractor from my boss, it came with the brush hog, rake and scraper blade for $1000.00 he said he coulded get it stopped and had no use for it. His lost my gain. Thanks again i should beable to fix it for looks like under $100.00 Bob Kohl.

Wow- you got a great deal!

 

[Stumpy]

$1000? Wow you lucky..... I'll trade ya for my L175! Low hours! I promise I ran before I took it apart

Sounds like he got scared of the machine and just wanted to get rid of it rather than do a little bit of research or ask for help. His loss.

 

[Piker]

Hodge, thanks for the confirmation regarding the internal ORC. I guess prior to 1980 they didn't have one, but from what I can tell mine has one. Also, just got a Bush Hog 48" 3 point finish mower since I first posted this morning - $200, from my buddy I bought the tractor from 1.5 yrs. ago. He's delivering it tomorrow & may exchange it for the labour to mill parts for 14 cabinet doors. He's also considering selling me his 48" Bush Hog bush hog (?). Don't have a lot of use for either but can't pass up a deal.

 

[B7100]

My 1978 B7100's got an ORC,I wonder if a mod was done at a later date?
Dave

Edit: just re read my post and noticed its my 300th post,cor i must have been here some time!!

 

[Stumpy]

If it's internal unlikely, it's probably a production change. Adding an internal overrunning clutch to a transmission not designed for one would require a very skilled and very bored machinist.

 

[Kytim]

my '77 model b7100 does not have an Internal ORC. would be interesting to know where the change break is in regard to serial number.

 

[Lil Foot]

My 1980 B7100DT (serial #B7001-67625) has the internal ORC.

 

[B7100]

My B7100 serial no: 52661 and has internal ORC, 1978??
smud6ie