manitou mla 628 hyd/steering

[thewhinboy]

My problem is when I use joystick I have to wait 50 to 60 seconds or longer for hyd. to work,Then when I move F or R and use steering hyds go very slow or stop. Have tried cleaning priority valve on intake plate on spool bank. also potentiometer @ injector pump but no joy Have been told to check pressure on accumulator or adjust pressure valve on top of hyd pump? How do I check pressure on these, any other suggestions appreciated Thanks in advanced

 

[ACEngineering]

My problem is when I use joystick I have to wait 50 to 60 seconds or longer for hyd. to work,Then when I move F or R and use steering hyds go very slow or stop. Have tried cleaning priority valve on intake plate on spool bank. also potentiometer @ injector pump but no joy Have been told to check pressure on accumulator or adjust pressure valve on top of hyd pump? How do I check pressure on these, any other suggestions appreciated Thanks in advanced

the potentiometer is calibrated to the pump ECU if that isn't right your wasting your time. only some one with the tool to plug in to the ecu can check and calibrate the Pot switch. first think I replace is the pot switch and the linkage for it as they wear out once that's all good then start looking else were.

you can try removing the glass fuse in the tool box behind the seat to see if the pump goes to 100% pumping all the time just as a temporary thing although it does not always revert the pump back to 100% depending on the fault so still don't rule out the pot switch etc.

To check pressure on pilot circuit you need tee in to the accumulator which is awkward to get to as its a cab seat out and cab floor out job. However the easy way if you have a LSU model with rollers on the joystick is to tee in to the pilot oil supply for the aux and extension solenoids under the front cover under boom. your looking for 30 to 35 bar pressure I think max its not adjustable its set via the accumulator supply block and comes as one complete unit. I doubt you have a pilot pressure issue other than maybe a blown accumulator which is the normal thing but that just means you wont release pressure from circuits with engine off.

F/R lever is not connected to hydraulics. but by engaging it you drop the engine speed if its not calibrated right then the drop in engine speed can be enough to make pump go to 60% flow or less depending on how its been set up. it should be on 60% flow below 1100rpm all the time then only switch to 100% flow above 1100rpm. if engine speed measured at alternator is 50 to 100 rpm lower than the calibrated rpm from the theoretical throttle pedal position the ecu shuts pump down by up to 60% flow or less if the default setting has been altered to compensate for lack of engine power available. the RPM range increases at higher revs as there is more power available so less need for the ecu to be so sensitive.

if the system has a fault, broken wire or the calibration setting goes out due to knackered pot switch or worn linkage or someone fiddled with it then the system goes in to a safe mode and only 30% flow barely enough for steering and brakes only.

Does that make any sense?

 

[ACEngineering]

My problem is when I use joystick I have to wait 50 to 60 seconds or longer for hyd. to work,Then when I move F or R and use steering hyds go very slow or stop. Have tried cleaning priority valve on intake plate on spool bank. also potentiometer @ injector pump but no joy Have been told to check pressure on accumulator or adjust pressure valve on top of hyd pump? How do I check pressure on these, any other suggestions appreciated Thanks in advanced

do not adjust anything on the hyd pump! you will get in a right muddle going in blind fiddling with pressure adjusters willy nilly.

 

[Forever Fendt]

My problem is when I use joystick I have to wait 50 to 60 seconds or longer for hyd. to work,Then when I move F or R and use steering hyds go very slow or stop. Have tried cleaning priority valve on intake plate on spool bank. also potentiometer @ injector pump but no joy Have been told to check pressure on accumulator or adjust pressure valve on top of hyd pump? How do I check pressure on these, any other suggestions appreciated Thanks in advanced

if you within 100 mile oxford get Ace to come look at it

 

[thewhinboy]

Thanks AC,Very well explaned and makes a lot of sense, Have pot switch checked by mantou scanner and everything is ok , also when i take out out glass it no difference .Just will not work hyd on joystick for about 1 to 2 minutes then ok to when i use steering then hyd go very slow or stop, then i haveto start all over again P/S steering works good at all times. Thanks

 

[ACEngineering]

Thanks AC,Very well explaned and makes a lot of sense, Have pot switch checked by mantou scanner and everything is ok , also when i take out out glass it no difference .Just will not work hyd on joystick for about 1 to 2 minutes then ok to when i use steering then hyd go very slow or stop, then i haveto start all over again P/S steering works good at all times. Thanks

Assuming ecu and pot switch are right and you have the right pilot pressure then Next step is to fit new priority valve then I guess which is in the inlet section of the main spool block and approx cost is £800 to £900 for the valve plus some seals.

 

[Curt]

Ours has done something similar to this, however it's only done 700 hours, could all this still be related at such low hours? Everything works just all hydraulics slow and even slower when steering etc. increasing rpm makes very little difference to speed of hydraulics

 

[ACEngineering]

Ours has done something similar to this, however it's only done 700 hours, could all this still be related at such low hours? Everything works just all hydraulics slow and even slower when steering etc. increasing rpm makes very little difference to speed of hydraulics

700hours? MLA 628 at there youngest is now just over 6 years old!
Stop production in Oct 2009 ish same times redrock went bust.

had a new hour clock or 2 by any chance?
Any trouble with hydraulics on any LSU Manitou 2003 to 2007 first thing to look at is potentiometer switch and its settings before doing anything else as most of the time this is were the problem is. Plus its the cheapest bit new pot switches less than fifty quid and couple quid for new ball joints on linkage. But you will need someone with the Manitou pad or the BB3 controller to check adjust settings.

Problems with the priority valve will generally come with oil contamination I personally have never had to replace one on any Manitou I have done one long long time ago but it turned out to be a different problem and I was wrong.

 

[Curt]

Yes definitely only done 700 hours. 2008 model Bought in 2012 off a claas dealer with 100 hours on it. Still had most of the "rubber hairs" on the original tyres, plastic on the seat etc. Some hobby farmer bought 2, used one then bought a fleet of claas tractors so decide to have the telehandlers to match aswell!
Will check everything you've mentioned, thanks for your help!

 

[ACEngineering]

Yes definitely only done 700 hours. 2008 model Bought in 2012 off a claas dealer with 100 hours on it. Still had most of the "rubber hairs" on the original tyres, plastic on the seat etc. Some hobby farmer bought 2, used one then bought a fleet of claas tractors so decide to have the telehandlers to match aswell!
Will check everything you've mentioned, thanks for your help!

Check wires on the pot switch on throttle linkage are not broken off check for play on the linkage aswell. Then get it recalibrated and go from there.

 

[ACEngineering]

Yes definitely only done 700 hours. 2008 model Bought in 2012 off a claas dealer with 100 hours on it. Still had most of the "rubber hairs" on the original tyres, plastic on the seat etc. Some hobby farmer bought 2, used one then bought a fleet of claas tractors so decide to have the telehandlers to match aswell!
Will check everything you've mentioned, thanks for your help!

As yours is effectively new a few pointers.

Front steering ram pins tighten them up FT with long bar helps stop them wearing and slopping about in chassis later in life.

Grease rear axle pivot every 50hrs at least but jack rear chassis off the ground on pick up hitch mounting bracket first so grease gets to the top were the weight sits and wears it out. Carefull with hitch as mounting isnt very strong so dont jack up by using a block wood under hitch hook. Use a bottle jack under the mounting bracket further back.

Regularly blow out the rads paying close attention to the one at bottom for transmission they block easy and hardest to clean due to design of rad.

Put a blob of sealent or glue etc on the three wires on the potentiometer switch stops the wires breaking off.

Drop a magnet in bottom of hyd tank to catch the metal which tends to come from the crap design of steering ram piston.

Grease door hinges regular or they block up.

 

[thewhinboy]

Is it possible that there could air in the hyd system as new hyd pipe fitted to boom six months a go. Also dose hyd filter inside tank give much trouble thanks

 

[ACEngineering]

Is it possible that there could air in the hyd system as new hyd pipe fitted to boom six months a go. Also dose hyd filter inside tank give much trouble thanks

No and no.
You will hear if them pumps have air in them they make hell of a noise!
You could check suction filter in bottom of tank but again if its blocked pump will make very nasty noises.

I think you will just have to spend some money on it. Clean tank out and new filters and inlet section/steering priority valve. There could be 4 hyd filters by the way.
Suction filter. Brake filter. Pilot filter and main return filter.

 

[Richard Henry]

No and no.
You will hear if them pumps have air in them they make hell of a noise!
You could check suction filter in bottom of tank but again if its blocked pump will make very nasty noises.

I think you will just have to spend some money on it. Clean tank out and new filters and inlet section/steering priority valve. There could be 4 hyd filters by the way.
Suction filter. Brake filter. Pilot filter and main return filter.

My problem is when I use joystick I have to wait 50 to 60 seconds or longer for hyd. to work,Then when I move F or R and use steering hyds go very slow or stop. Have tried cleaning priority valve on intake plate on spool bank. also potentiometer @ injector pump but no joy Have been told to check pressure on accumulator or adjust pressure valve on top of hyd pump? How do I check pressure on these, any other suggestions appreciated Thanks in advanced

Hi have the same problem with my 628 did u ever find out wat was wrong thanks in advance

 

[ACEngineering]

Hi have the same problem with my 628 did u ever find out wat was wrong thanks in advance

Start from the beginning, cause this old thread and might not even be the same as you machine?

What machine model and age? MLT or MLA. if MLA full model number and series.
Describe the problems

 

[Richard Henry]

Start from the beginning, cause this old thread and might not even be the same as you machine?

What machine model and age? MLT or MLA. if MLA full model number and series.
Describe the problems

 

[Richard Henry]

Mla 628t 120 lsu ps
When u use the steering before the joystick it takes 30 to 60sec before anything on the joystick will work again.i Pressure tested the ls line it's 35 bar??

 

[ACEngineering]

Mla 628t 120 lsu ps
When u use the steering before the joystick it takes 30 to 60sec before anything on the joystick will work again.i Pressure tested the ls line it's 35 bar??

What LS line where?

 

[Richard Henry]

Wat should I check next??

 

[ACEngineering]

Wat should I check next??

Where exactly did you test this 35bar?