B7100D

Lil Foot

Well-known member
Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,515
2,545
113
Peoria, AZ
Most likely the 3 pt piston seals:
3pt seals.jpg
 

torch

Well-known member

Equipment
B7100HSD, B2789, B2550, B4672, 48" cultivator, homemade FEL and Cab
Jun 10, 2016
2,617
864
113
Muskoka, Ont.
I got a B7100D not to long ago, and the 3-point doesn't stay up. Any one have an idea why?
Over what period of time? If it sinks down in minutes with no load, then yeah, rebuild it. If it sinks down over hours or days while supporting an implement then a rebuild may not help -- some seepage is normal and even a brand new one often sinks over days under load.
 

Lil Foot

Well-known member
Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,515
2,545
113
Peoria, AZ
Don't know the size, I just went to the dealer and picked them up. If I remember right, there is an o-ring and backup ring on the piston, and two o-rings that seal the cover.
 

nathaniel

New member

Equipment
B7100 Kabota
Apr 29, 2023
13
1
3
Carguy08
Yes there are 2 o-rings on the cover, they're fine. The piston only had 1 ring on it but, i am not the first owner thow, so no telling what happend to the 2nd o-ring on the piston.
 

Lil Foot

Well-known member
Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,515
2,545
113
Peoria, AZ
The second ring on the piston is a backup ring, like these:

burimages.jpeg
mbnp-95x2-5x2-5.png
 

Lil Foot

Well-known member
Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,515
2,545
113
Peoria, AZ
According to my ancient parts manual/list:
(sometimes I find the numbers from this old list have been superseded by newer numbers)
partsdia.jpg
oring.jpg
buring.jpg
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
30,180
6,350
113
Sandpoint, ID
Some of the very first models only had the O-ring.
Not the back up ring.
They are not interchangeable as they are different pistons.
If there is no gap behind the O-ring it's very likely you have an older model.
I personally would get the newer piston that takes the back up ring.
 

nathaniel

New member

Equipment
B7100 Kabota
Apr 29, 2023
13
1
3
Carguy08
Under the seat there is a valve and i is attached to the cover to the piston so you take those 4 bolts off and there is one more plate bolted on to the cover so take those 2 bolts off and the cover comes rite off you may have to twist it back and forth a bit but it comes off and as for the piston you can just use a magnet you pull the piston out.
 

AOW162435

Active member

Equipment
B7100
Jun 16, 2023
105
51
28
Ellicott City, MD
Under the seat there is a valve and i is attached to the cover to the piston so you take those 4 bolts off and there is one more plate bolted on to the cover so take those 2 bolts off and the cover comes rite off you may have to twist it back and forth a bit but it comes off and as for the piston you can just use a magnet you pull the piston out.
Thank you! That sounds way too easy.

Andreas
 
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