Fuel Leak - HDJ80

Justin_Elliott

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Ok just completed the power steering pump overhaul - which went fairly well - (still need to take it for a full run but initial signs looked good...

Until when running the new fluid into the pump I noticed a leak from the side of the fuel injector pump... :o

Location.jpg


The leak is coming from somewhere within the red box (and drips appear at the tip of the arrow.) unless I've misread the FSM this is the 'Thermo Wax' unit..

I've tried looking around the area to see where its seeping from but nothing is too obvious - any ideas?

If its the Thermo Wax doodah that is FUBAR'd anyone know how easy/expensive they are to replace???

Oh - and MOT is booked for 9th so only got a week to fix!!! So any help would be appreciated.
 

Justin_Elliott

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Ok - I've removed the fuel pipe (just under the Thermo Wax unit) and there is no sign of any damage so the leak must (?) be coming from the Thermo Wax unit...

After removing the Fuel Pipe and idle up lever I'm completely stumped over how to remove the thermowax unit. Its held on by two 5mm hex head bolts - but they seem to be trapped by the spring! Anyone ever removed this before?
 

Julian Voelcker

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You can remove it with an allen key, but you have to be careful - the last thing you want to be doing is undoing the springs.

Assuming it is is still working, hopefully you will just need to replace the O ring behing it, however more often than not the shaft could be too worn and it could be leaking from around it so you may need to replace the whole unit which is in the region of £240
 

Justin_Elliott

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Not going to touch the springs - I could tell that would be a disaster waiting to happen...

Other than replacing the O-ring and a visual check on the unit is there an easy way to tell if the shaft is too worn?

Presumably OEM spares are the only way to go - any Idea of the part number? Hopefully Mr Rubie can find a cheaper source...any other ideas??
 
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Justin_Elliott

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Ok finally managed to remove it using a ball ended allen key. Lower of the two bolts was tricky but got access through the wheel arch...

Anyway - replaced the O-ring (which looked knackered) gave the unit a close looking over and no signs of damage or wear (to be honest its mostly hidden by the spring!). But after reassembly the blasted leak is still there!!! :(
 

Justin_Elliott

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Firstly I've been referring to this unit as 'Thermo-Wax' (as per FSM) but its effectively the Automatic Cold Start Device (ACSD) or Cover Sub Assembly - Timer {according to EPC}... Eitherway it has part number 22790-17540 ['93-'94] or 22790-17141 ['90-'92]

I've been reading up on IH8MUD and came across these threads:
Replacement of ACSD using a similar part from another toy-truck: http://forum.ih8mud.com/diesel-tech-24-volts-systems/111970-1hdt-acsd-replacement.html

Removing the ACSD - Chucking it away and blanking off the hole: http://forum.ih8mud.com/diesel-tech-24-volts-systems/109211-1hd-t-idle-shake.html

Ok cost of replacing the unit is going to be expensive (see Julian's estimate above - pretty close!) I'm tempted with the lower cost swapout option but from reading IH8MUD there are claims that no difference can be noted without it at -12C so am I best just to strip it out for the time being?
 

Brett

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I replaced mine due to a leak, went down the same route as you, O-ring first then eventually replaced the whole ACSD unit due to the shaft being scored (as mentioned by Julian).

I found out about being able to blank off the port after I'd replaced the ACSD, if I'd found out before I'd have tried blanking it off.
 

Justin_Elliott

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I've chosen the easy route - replace as is. Decided not to take the gamble!

Ian quoted a respectable price but delivery could have been a problem (only by a few days though!). So chosen to go with OEM direct - via Parts-King in order to take advantage of the Club Discount of course...
 

Julian Voelcker

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The key thing with blanking off the ACSD is that you need to recheck the timing afterwards.

The ACSD works on the basis that it advances the timing when cold to aid starting and then retards it to normal when warmed up.

What actually happens is that the pump is in advanced start from cold and then as the plunger in the ACSD comes out it retards the timing to normal position.

This is why when you setup the timing properly you retard the timing by slotting a spacer into the ACSD device to simulate the effect of the plunger coming out as the engine heats up.

So, what this means is, if you start removing the ACSD device and blanking it off you will need to reset the timing on the pump.
 
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