Vacuum diff switch - believe its broken- NOW FIXED
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Vacuum diff switch - believe its broken- NOW FIXED
yesterday l found that the diff lock does not work.
l have checked that l am getting a vacuum at the switch - the black pipe that runs to the back of the induction manifold and there is good vacuum.
with the engine running and the pipes attached, the plunger in (in off pos) l can hear a noise from the vacuum switch unit - there is no sucking/blowing from the red or clear pipe ends.
with the engine running and the black pipe attached, the plunger out (in on pos) there is a vacuum from the red pipe but not the clear pipe.
does anybody have any experience of these vacuum switches? does mine appear broken? just missed a new one on ebay - it went for £32
if there are other tests l can do, please advise,
l have checked that l am getting a vacuum at the switch - the black pipe that runs to the back of the induction manifold and there is good vacuum.
with the engine running and the pipes attached, the plunger in (in off pos) l can hear a noise from the vacuum switch unit - there is no sucking/blowing from the red or clear pipe ends.
with the engine running and the black pipe attached, the plunger out (in on pos) there is a vacuum from the red pipe but not the clear pipe.
does anybody have any experience of these vacuum switches? does mine appear broken? just missed a new one on ebay - it went for £32
if there are other tests l can do, please advise,
Last edited by harry potter on Sun May 13, 2012 4:26 pm, edited 1 time in total.
They do wear out and I found the rubber that creates the vacuum perishes. I replaced mine as the cheaper option of replacing with a new part (which was stupid money).
I know you could grab a second hand one from a Rangie, but I didn't want to have to replace a worn part with another.
This is what I did http://www.stage1v8.org.uk/phpBB2/viewt ... hlight=cdl
I know you could grab a second hand one from a Rangie, but I didn't want to have to replace a worn part with another.
This is what I did http://www.stage1v8.org.uk/phpBB2/viewt ... hlight=cdl
Alan
1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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- firemanshort
- Posts: 378
- Joined: Fri Feb 10, 2006 2:42 pm
- Location: Loudoun County, VA - near Wash DC
I had this problem with mine once. I pulled the knob and no vaccum. I fussed with it testing it 6 different ways. Finally, on one of my tests, it pulled and extra 1/2 inch or so. It seems it was just dirty from lack of use and not pulling all the way out.
They do break and wear out, though.
Spray some cleaner / WD 40 or other potion around it and push it in and out a dozen or so times to really make sure that it is all the way out. Then start looking into a replacement.
They do break and wear out, though.
Spray some cleaner / WD 40 or other potion around it and push it in and out a dozen or so times to really make sure that it is all the way out. Then start looking into a replacement.
-----------------------------------
Firemanshort
Virginia, USA
Firemanshort
Virginia, USA
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evening all,
l have discovered why the diff lock is not working - a rust hole in the actuator unit itself.
l now have 3 vacume switches to try. one even has a light in the end of it!
reading through the manual (Rover V8 supplement) it instructs to remove unit without draining the transfer box oil -
if l remove the actuator will this not require the box to be drained of oil?
the misses will kill me if l removed the unit and flood the driveway with gear oil.
l had to remove the drivers floor pannel to get to the top of the diff unit.
thanks
l have discovered why the diff lock is not working - a rust hole in the actuator unit itself.
l now have 3 vacume switches to try. one even has a light in the end of it!
reading through the manual (Rover V8 supplement) it instructs to remove unit without draining the transfer box oil -
if l remove the actuator will this not require the box to be drained of oil?
the misses will kill me if l removed the unit and flood the driveway with gear oil.
l had to remove the drivers floor pannel to get to the top of the diff unit.
thanks
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- Joined: Thu Apr 30, 2009 12:39 pm
- Location: Essex, UK
Hmm, been there
You can remove the whole actuator housing in situ from above. Arguably one bolt is awkward due to the gearbox mount. Only a very small amount of oil will escape when you break the gasket seal so no need to drain off unless you need to. Don’t forget the felt seal between the actuator and housing otherwise the diff lock will engage ok but it won’t disengage – guess how I found that out Note* When reassembling I had to engage the diff lock to be able to achieve sufficient space to get the housing back in.
Good luck…
You can remove the whole actuator housing in situ from above. Arguably one bolt is awkward due to the gearbox mount. Only a very small amount of oil will escape when you break the gasket seal so no need to drain off unless you need to. Don’t forget the felt seal between the actuator and housing otherwise the diff lock will engage ok but it won’t disengage – guess how I found that out Note* When reassembling I had to engage the diff lock to be able to achieve sufficient space to get the housing back in.
Good luck…
1983 Stage 1 V8 Hardtop (Mrs Bingham)
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- Posts: 262
- Joined: Thu Mar 15, 2007 10:53 pm
- Location: Leamington Spa
l found this interesting thread on the DiffLock forum.
gives some interesting reading on this very topic.
l hope l havnt broken the spider gears.
http://forum.difflock.com/viewtopic.php?t=57492
gives some interesting reading on this very topic.
l hope l havnt broken the spider gears.
http://forum.difflock.com/viewtopic.php?t=57492
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why my diff lock didnt work - big rust hole didnt help.
a lot of sand and dried mud fell out. l have pulled the switch apart and that is full of sand too which has been drawn up.
pic to show the inside of the housing. home made gaskets.
replacement is very simple. l removed the drivers floor plate for access above.
drain transerbox oil oil to have a look at quality -
remove all bolts
lightly tap casing to remove the housing catch the spring and ball
clean up.
to remove the actuator - remove the switch - l didnt and have damaged it so require a replacement now
drive the roll pin out - send it down the switch hole - long slender punch does the job.
to get the selector fork in position, move the slider on the shaft forward and wiggle the unit back into place-
should take no more than 1 hour to replace - (includes cleaning and making new gaskets ect)
all my replacement switches do not work - the rubber slider in the switch does not form a good seal due to corrorsion inside.
the picture in the previous posts of the switch - the previous owner had put the pipes on incorrectly. l believe the black pipe which draws the vacuum from the engine should be in the middle pipe.
the red pipe which runs to the front of the actuator which engages the diff lock should be on the top pipe and the yellow pipe should be on the bottom pipe (correct) this runs to the other pipe on the actuator pulling the diff lock off.
l am able to engage the diff lock but have to swap the pipes round on the switch to pull it off agian. to clean the switch l need to remove the small roll pin that holds the black plunger onto the metal shaft which then allows the simple rubber plate to be cleaned. l will upload some internal pic of the switch for anybodys interest incase they havent opended theirs.
if anybody has any comments on the correct instalation of pipes please say, l havent found a diagram that shows the orientation of the pipes.
a lot of sand and dried mud fell out. l have pulled the switch apart and that is full of sand too which has been drawn up.
pic to show the inside of the housing. home made gaskets.
replacement is very simple. l removed the drivers floor plate for access above.
drain transerbox oil oil to have a look at quality -
remove all bolts
lightly tap casing to remove the housing catch the spring and ball
clean up.
to remove the actuator - remove the switch - l didnt and have damaged it so require a replacement now
drive the roll pin out - send it down the switch hole - long slender punch does the job.
to get the selector fork in position, move the slider on the shaft forward and wiggle the unit back into place-
should take no more than 1 hour to replace - (includes cleaning and making new gaskets ect)
all my replacement switches do not work - the rubber slider in the switch does not form a good seal due to corrorsion inside.
the picture in the previous posts of the switch - the previous owner had put the pipes on incorrectly. l believe the black pipe which draws the vacuum from the engine should be in the middle pipe.
the red pipe which runs to the front of the actuator which engages the diff lock should be on the top pipe and the yellow pipe should be on the bottom pipe (correct) this runs to the other pipe on the actuator pulling the diff lock off.
l am able to engage the diff lock but have to swap the pipes round on the switch to pull it off agian. to clean the switch l need to remove the small roll pin that holds the black plunger onto the metal shaft which then allows the simple rubber plate to be cleaned. l will upload some internal pic of the switch for anybodys interest incase they havent opended theirs.
if anybody has any comments on the correct instalation of pipes please say, l havent found a diagram that shows the orientation of the pipes.
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Looks good, but I will comment on the green gasket you’ve made. Originally it would have had a felt washer over the actuator shaft sandwiched between the housing and actuator. A gasket isn’t suitable and I am worried because the actuator flange is prone to bending thus not allowing a vacuum seal between the two units. A leak here will prevent the diff lock from disengaging!!! I think I can see the rubber o-ring in the housing but that just stops the oil from being drawn out. Also be mindful on whether you have the correct bolts for the actuator unit. Mine were countersunk so if you use regular bolts you risk splitting the housing flange if over tightened
There isn’t an exact science on the pipe fitment but obviously easy to work out. Common sense would suggest the red one is for diff lock on (front of actuator) and yellow for diff lock off (rear of actuator) but this counts for nothing if the plunger orientation is wrong. From memory I can’t remember which way is which, but a simple suck test should sort that out but you would think the middle one is the feed from the engine. I can confirm this tomorrow if necessary.
FYI
Felt Washer 591345 but easily home made.
There isn’t an exact science on the pipe fitment but obviously easy to work out. Common sense would suggest the red one is for diff lock on (front of actuator) and yellow for diff lock off (rear of actuator) but this counts for nothing if the plunger orientation is wrong. From memory I can’t remember which way is which, but a simple suck test should sort that out but you would think the middle one is the feed from the engine. I can confirm this tomorrow if necessary.
FYI
Felt Washer 591345 but easily home made.
1983 Stage 1 V8 Hardtop (Mrs Bingham)
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thank you for the felt washer part number. there was not a washer fitted when l removed the unit, there was just the gasket which is why made another one.
lesson learned - do not go on what the previous owner has done! also there was only one counter sunk bolt, not the two!
l am assuming (hate thay word - never assume - always prove) that there is a good seal between the actuator and the housing as the diff lock does disengage when the pipe work is swapped on the switch unit.
then diff lock engages and ungages when the pipe work swaps on the switch.
my next stage is to strip out some switches - clean up and re-build.
await some progress photos!
ps- theres some local RTV trials comp very close to home that l want to get the truck ready for next sunday. pressures on.
thanks
lesson learned - do not go on what the previous owner has done! also there was only one counter sunk bolt, not the two!
l am assuming (hate thay word - never assume - always prove) that there is a good seal between the actuator and the housing as the diff lock does disengage when the pipe work is swapped on the switch unit.
then diff lock engages and ungages when the pipe work swaps on the switch.
my next stage is to strip out some switches - clean up and re-build.
await some progress photos!
ps- theres some local RTV trials comp very close to home that l want to get the truck ready for next sunday. pressures on.
thanks
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