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Allis chalmers and jcb problems

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Sreamerbeast

Member
Joined
Oct 9, 2008
Messages
16
Location
Knoxville
Occupation
Scrap handler.
hey all hope you can help I got a allis chalmers wheel loader and there is somthing wrong with the trans in it, when i first start it or let it idle it wont movie unless you hold it wide open or feather the throttle its like it is hesitating to go into gear. Now the jcb wheel loader runs good when first started but as it gets warmer it moves slower lol it is hydrostatic with a perkins 4 in it and cant figure out why it over heats the trans temp is normal but the motor gets hott and slows the loader down kinda weird if you ask me i forgot to look at the model numbers so ill let you know on that tomorrow. thanks for the help:beatsme
 
S

Sreamerbeast

Member
Joined
Oct 9, 2008
Messages
16
Location
Knoxville
Occupation
Scrap handler.
OK I finally got the model numbers

The allis chalmers is a 840 wheel loader and the jcb is a 407b wheel loader please help guys thank you
 
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ogs1022

New Member
Joined
Nov 3, 2008
Messages
2
Location
Wisconsin
Occupation
Technical Trainer for Construction OEM
Jcb

The issue with the JCB I have experienced before. With the hydrostatic drive system there is an "inching" function. This function gives the ability to neutralize the variable pump and give the machine full throttle for full pressure to your working functions (separate from drive). This inching function is controlled one of two ways on the variable pump. Either by an inching valve mounted on top or by a cable attached to the "DA pressure" valve on the pump. When this circuit is being activated without command by the operator stepping on the brake pedal it will be more evident when the hydraulic fluid warms up. Machine will get slow and sluggish due to the fluid thinning out and more will be bypassed back to the tank via this circuit. First and foremost...ensure the brake pedal is coming all the way up when you take your foot off of it. Ensure by reaching down and pulling up on it. If that does not fix it, then there is something with the associated linkage. Start there.
 
A

assocpowertrain

Member
Joined
Jun 15, 2009
Messages
22
Location
Oregon
ogs1022 said:
The issue with the JCB I have experienced before. With the hydrostatic drive system there is an "inching" function. This function gives the ability to neutralize the variable pump and give the machine full throttle for full pressure to your working functions (separate from drive). This inching function is controlled one of two ways on the variable pump. Either by an inching valve mounted on top or by a cable attached to the "DA pressure" valve on the pump. When this circuit is being activated without command by the operator stepping on the brake pedal it will be more evident when the hydraulic fluid warms up. Machine will get slow and sluggish due to the fluid thinning out and more will be bypassed back to the tank via this circuit. First and foremost...ensure the brake pedal is coming all the way up when you take your foot off of it. Ensure by reaching down and pulling up on it. If that does not fix it, then there is something with the associated linkage. Start there.
Click to expand...

this is some great info here...
 
D

drcwright

New Member
Joined
Aug 17, 2009
Messages
3
Location
South Carolina
I have an 840 also. Brake booster was leaking and we removed it to rebuilt but can't find a repair kit. So we put it back on and now have lost our steering. Any suggestions?
 
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drcwright

New Member
Joined
Aug 17, 2009
Messages
3
Location
South Carolina
Thanks. Got the brake booster kit, installed it and have brakes! But my steering won't work now. Have fluid going into system. Maybe airlocked? Any suggestions?
 
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