Crown FC-4000:
FC4000 Making strange noise

Hi All,

I am new to the forum and a new forklift owner so forgive me if I use the wrong terms or wording.

I recently purchased a used crown FC-4000. The forklift works beautifully. The steering, drive motor, breaking, and mast all function as they should. The only issue I'm having is a strange noise that is coming from the engine compartment when the forklift is in park. Here is what the symptoms are:

I turn the forklift on and everything starts up and sounds completely normal. After about 20-30 seconds an unusually load humming/vibrating noise comes from underneath the foot plate. When I take it off the parking break the noise goes away and all sounds and works fine. As long as I am driving and using the forklift no noise is being made. When put back into park (about 10-20 seconds later) the noise comes back on.

I had a chance to read thought the service manual and I have a strong feeling it is something to do with the steer motor going into a low pressure state once the accumulator reaches a high enough pressure since I only hear the noise when the forklift is not being used and parking break is engaged.

The forklift is a 2007 with about 13,000 hours. There are no modifications or aftermarket parts on the forklift that I know of. Do you guys have any suggesting on what it may be? Or maybe have any other steps you would suggest to troubleshoot the forklift a bit more.

Any help is greatly appreciated!
  • Posted 7 Apr 2015 00:30
  • Discussion started by Dreech
  • Ohio, United States
Showing items 1 - 10 of 10 results.
Hi yes is very comon in this models re hard to fix
Tha noise and pulsation almos change and
Remplace al system and stops for while and
Came back again make me crazy and put
Check valve next to the alve asemble and
Reduce the noise little and stil the brake system is
Working ok crown telme need to bleed
The system whit crown special tools and
Inyected nitro in the system (acumulator)
And works fine but spence.
  • Posted 14 Dec 2018 07:13
  • Reply by armando_g
  • California, United States
Johngr please read southervikings comment about a techs death in the USA. My advice echoes his if your not a trained tech don't mess about with this truck.
  • Posted 18 Mar 2016 08:09
  • Reply by lifter01
  • West Yorkshire, United Kingdom
Hi, do you have a solution for this problem. I have a same type situation. Also I want to know how do i access unloading valve of steer pump so i can adjust.
  • Posted 18 Mar 2016 01:08
  • Reply by JohnGR
  • Attika, Greece
It may well be but it also could b the vavle, I am a tech, I would attempt to adjust vavle first, then sell a part to customer, but I have the training and tools.
  • Posted 21 Apr 2015 08:18
  • Reply by southernviking
  • South Island, New Zealand
Sorry for such a late response. I had sent a video over to the crown dealer and they suggest it is an accumulator that has gone bad. Which honestly doesn't make too much sense to me. I would image a noise like that would likely be a bad valvle. Do you think it could possibly be the accumulator going/gone bad?
I would add a video of the noise to the forum but not sure how to do that...
  • Posted 21 Apr 2015 06:27
  • Reply by Dreech
  • Ohio, United States
No problem, it is mostly a nuisance, it does not effect the truck, it is a dangerous process to one untrained, and being a mechanic death recently in the US, it's best to cal a technician if you would like to solve the vibration noise, I think access is underneath.
  • Posted 10 Apr 2015 15:22
  • Reply by southernviking
  • South Island, New Zealand
Dean_F again I greatly appreciate you taking the time to look into this and helping us out. I am no expert with Forklifts and please excuse my lack of knowledge in this topic. But how do you go about adjusting the unloading valve (if possible by a user)? Also, if the unloading valve does need replaced is it a fairly easy DIY fix or something we would need to call crown in to do?
  • Posted 10 Apr 2015 11:26
  • Reply by Dreech
  • Ohio, United States
It seems it could be to do with the steer pump hydraulics, adjusting the unloader valve, seems to eliminate the problem, a new valve, but happens often with this model, we get it here as well.
  • Posted 10 Apr 2015 11:00
  • Reply by southernviking
  • South Island, New Zealand
Great I really appreciate your response and help!
  • Posted 10 Apr 2015 04:00
  • Reply by Dreech
  • Ohio, United States
I think it's the brake system, it's a nuisance problem nothing serious, to do with the unloaded valve or something, I will check at work later and post more.
  • Posted 10 Apr 2015 02:34
  • Reply by southernviking
  • South Island, New Zealand

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