Unstable Unimog

[pat356jones]

I have a Unimog FLU419. It's been a great vehicle but when you lift off the throttle, the vehicle becomes unstable, wanting to swerve back and forth so it doesn't feel safe. When you apply throttle again it stabilizes. The more quickly you lift off the throttle, the more radical the swerving. It used to be very stable and it used to go over 50mph but now it only goes 40mph and has this swerving problem. The only change we've made is to remove the part of the fuel filter which appears to be a bypass of some sort. If anyone knows what is causing this I appreciate your input.

 

[workerdrone]

You posted this in parts for sale @pat356jones

I'd delete and try the Unimog subforum

 

[pat356jones]

Thanks. I don't see the Unimog subforum but agree I should post it there. Do you have a direct link?

 

[Kmrtnsn]

Sounds like it is engine braking.

 

[pat356jones]

Sounds like it is engine braking.

Thanks. What's the remedy for engine braking?

 

[Nukeproof]

engine braking is good, and you want that. but it does sound like you may have an alignment or front end issue where the weight transfer of the car is causing the unstable feeling.

i dont mean to sound condesending, but if you dont understand that there isnt really anything we can do on the internet to help, other that suggest a visit to a proper shop.

 

[Kmrtnsn]

i once had an old Ford pickup that did something similar. It had a really bad idler arm that would shift position when the steering components settled on braking or acceleration, the toe changed so much it gave a whole new meaning to power steering. Either two things are happening, you have a similar worn steering component issue or when your engine brakes it has sufficient power to break traction shifting the load all the way down through the drive components in four wheel drive, like downshifting slowing coming off of coasting. I've seen something similar driving on ice in an old 4x4 truck but moving that thing always presented some kind of issue every time you started it.

Is yours a SEE with all of the equipment on it?

 

[Rallyroo]

Thanks. I don't see the Unimog subforum but agree I should post it there. Do you have a direct link?

Here you go....

Unimog and MB Truck

Unimog and Unimog Campers.

expeditionportal.com

 

[pat356jones]

engine braking is good, and you want that. but it does sound like you may have an alignment or front end issue where the weight transfer of the car is causing the unstable feeling.

i dont mean to sound condesending, but if you dont understand that there isnt really anything we can do on the internet to help, other that suggest a visit to a proper shop.

Yep - it has been at a good shop but has been on the back burner for a while because I didn't need it right away. I told the shop owner I will need it for a project coming up and today he found the problem. I'm embarrassed to say I could probably have discovered it myself had I crawled underneath because two bolts were missing from two sway bars or stabilization bars from the frame to the rear differential or rear end. Thanks everyone for your help! I'm not sure how to end this post so I'll respond to all so everyone will know this case is solved. Thanks!

 

[pat356jones]

i once had an old Ford pickup that did something similar. It had a really bad idler arm that would shift position when the steering components settled on braking or acceleration, the toe changed so much it gave a whole new meaning to power steering. Either two things are happening, you have a similar worn steering component issue or when your engine brakes it has sufficient power to break traction shifting the load all the way down through the drive components in four wheel drive, like downshifting slowing coming off of coasting. I've seen something similar driving on ice in an old 4x4 truck but moving that thing always presented some kind of issue every time you started it.

Is yours a SEE with all of the equipment on it?

Yes, it's a SEE with all the equipment on it, including backhoe, bucket, a hydraulic chainsaw and jackhammer. I'm embarrassed to say I could probably have discovered the problem myself had I crawled underneath because two bolts were missing from two sway bars or stabilization bars from the frame to the rear differential or rear end. Thanks everyone for your help! I'm not sure how to end this post so I'll respond to all so everyone will know this case is solved. Thanks!

 

[pat356jones]

Sounds like it is engine braking.

I'm embarrassed to say I could probably have discovered the problem myself had I crawled underneath because two bolts were missing from two sway bars or stabilization bars from the frame to the rear differential or rear end. Thanks everyone for your help! I'm not sure how to end this post so I'll respond to all so everyone will know this case is solved. Thanks!

 

[Nukeproof]

Yes, it's a SEE with all the equipment on it, including backhoe, bucket, a hydraulic chainsaw and jackhammer.

just saw one of them yesterday here in Arizona

glad you got it fixed, or fixing.

 

[Kmrtnsn]

Glad you got it fixed! You're my hero this week! I've always wanted enough land to have a SEE, looks like an incredibly useful tool to have around, especially for the price I've seen on some. I'm very jealous!

 

[Rallyroo]

Glad you fixed the problem. I've gotten into a habit to crawl under my truck after long trips on washboard roads. I've found bolts that have loosened up a few times.