redhawk23
ArboristSite Operative
Last question, is a tool necessary to reinstall the crank?
Dolmar 421 crank seal, bearing removal
- Thread starter redhawk23
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fordf150
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nope.
I’ll give them a spray over with degreaser and water if they are bad before splitting it right down - mostly so I can see what I’m working on. Then when it’s in bits I’ll deep clean it.
However if I’m only repairing a certain part - like the top end, I’ll give it a really good clean to ensure when I do take it apart no crap falls in and gets In the bottom end, or in thread holes etc.
However if I’m only repairing a certain part - like the top end, I’ll give it a really good clean to ensure when I do take it apart no crap falls in and gets In the bottom end, or in thread holes etc.
No, but it’s nice to have, that’s for certain.
Alternatively you’ll need a heat source.
Fatherwheels
Addicted to ArboristSite
Heat the bearing in your hand or in the sun for a while, this will expand it to fit
over the crank shaft, use some of the compounds mentioned earlier to stick it to
the shaft, a rub around the shaft and bearing bore before sliding it on, then dry
up any excess, then let it all cool way down, the cooling of the bearing / now on the
shaft, will help it fit into the case, as it will be smaller, make sure and heat the case
with a hair dryer or such to expand the pocket the bearing needs to fit into, then as
in the video s in this thread, coat the bearing with the mentioned compounds to stick
it into the case, do one side at a time, but have them both ready to go, you will need to
stick the gasket that goes between the two case halves to one of the halves with a light
smear of grease this will help it from sagging down and falling into the case before you get
the bolts all in to hold it in place, be gentle so the gasket sits and covers the joint well.
Tighten the case bolts diagonally, lets say top left, then bottom right then top right then
bottom left, and work your way around, best to start in the center and apply that technique.
Go gently and if possible use a torque spanner, they make small ones for bicycles and such
that will work well and protect the magnesium threads and ensure all bolts are under the same pressure.
over the crank shaft, use some of the compounds mentioned earlier to stick it to
the shaft, a rub around the shaft and bearing bore before sliding it on, then dry
up any excess, then let it all cool way down, the cooling of the bearing / now on the
shaft, will help it fit into the case, as it will be smaller, make sure and heat the case
with a hair dryer or such to expand the pocket the bearing needs to fit into, then as
in the video s in this thread, coat the bearing with the mentioned compounds to stick
it into the case, do one side at a time, but have them both ready to go, you will need to
stick the gasket that goes between the two case halves to one of the halves with a light
smear of grease this will help it from sagging down and falling into the case before you get
the bolts all in to hold it in place, be gentle so the gasket sits and covers the joint well.
Tighten the case bolts diagonally, lets say top left, then bottom right then top right then
bottom left, and work your way around, best to start in the center and apply that technique.
Go gently and if possible use a torque spanner, they make small ones for bicycles and such
that will work well and protect the magnesium threads and ensure all bolts are under the same pressure.
redhawk23
ArboristSite Operative
My current torque wrench isn’t going to work. I’m considering the
ACDelco ARM601-3 3/8” (3.7 to 37 ft-lbs.). I’m wondering if covers the screws that especially requiring accurate torquing. Here’s a table on the torques for my saw. I assume the units are ft-lbs.
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Fatherwheels
Addicted to ArboristSite
That torque goes all the way down to 3.5 lbs, so it should be fine.
I would consult with @fordf150 regarding whether those figures
on your list are ft lbs or Newton meters,
for example 10 Nm = 7.375621493 ft lbs as calculated
here, https://www.unitconverters.net/energy/nm-to-ft-lb.htm
you wouldn't want to get them mixed up, I think they are ft lbs
but its better to be sure.
I would consult with @fordf150 regarding whether those figures
on your list are ft lbs or Newton meters,
for example 10 Nm = 7.375621493 ft lbs as calculated
here, https://www.unitconverters.net/energy/nm-to-ft-lb.htm
you wouldn't want to get them mixed up, I think they are ft lbs
but its better to be sure.
redhawk23
ArboristSite Operative
Update:
I’m waiting for my backordered parts, and it’s a good thing because I added items to my order a few times.
I haven’t split the case yet, though I did give it a few wacks with a mallet. It didn’t budge. I’ll probably have a shop split it because I have an aversion to owning the tool.
I got some of that purple cleaner, it did a great job of cleaning up the case. I’d have used it earlier but i wasn’t familiar with it.
I asked 2 mechanics about the units of torque in the manual that was shared above and they didn’t know and said they’ve never used a torque wrench on a saw in their life. I’ll ask third.
thanks for all the help
PS
I didn’t know repair manuals existed for each model saw. I always wondered how mechanics knew how to install the little plastic bits and springs that are unique to a saw.
I’m waiting for my backordered parts, and it’s a good thing because I added items to my order a few times.
I haven’t split the case yet, though I did give it a few wacks with a mallet. It didn’t budge. I’ll probably have a shop split it because I have an aversion to owning the tool.
I got some of that purple cleaner, it did a great job of cleaning up the case. I’d have used it earlier but i wasn’t familiar with it.
I asked 2 mechanics about the units of torque in the manual that was shared above and they didn’t know and said they’ve never used a torque wrench on a saw in their life. I’ll ask third.
thanks for all the help
PS
I didn’t know repair manuals existed for each model saw. I always wondered how mechanics knew how to install the little plastic bits and springs that are unique to a saw.
redhawk23
ArboristSite Operative
Asked a mechanic how he split cases and he said he pries them apart with a screw driver and chisel!
I’m getting the impression from the few mechanics I’ve talked to that opening a case is done very infrequently.
One mechanic didn’t think a seal leak was enough to generate my problem of the saw starting and stopping. Did I miss something else? How often do carbs require more than a hose down with carb cleaner? Are leaking seals uncommon and do they always need to be repaired?
just ordered some loctite 620. Is there precious metals in that stuff?
I’m getting the impression from the few mechanics I’ve talked to that opening a case is done very infrequently.
One mechanic didn’t think a seal leak was enough to generate my problem of the saw starting and stopping. Did I miss something else? How often do carbs require more than a hose down with carb cleaner? Are leaking seals uncommon and do they always need to be repaired?
just ordered some loctite 620. Is there precious metals in that stuff?
redhawk23
ArboristSite Operative
I’m going to try splitting the case by heating the case with a propane torch and hitting the crank with a mallet. My little rubber and plastic mallet is falling apart. What kind of mallet is appropriate for smacking the crank?
thanks
thanks
copper or alloy, with the nut screwed on flush, i,ve never had to use heat (only on assembly)
redhawk23
ArboristSite Operative
I gave it a few wacks with a small mallet I had and it didn’t work. Not heavy enough? Too shock absorbent?
thanks, I’ll try a metal mallet
thanks, I’ll try a metal mallet
i usually shove wedges in near the boltholes, you have to make sure you dont scar the faces tho eh
redhawk23
ArboristSite Operative
Think a 20 ounce brass hammer is sufficient?
redhawk23
ArboristSite Operative
I’m not sure what you mean?
where the gasket is, with a flat screwdriver or 2 or 3
fordf150
ArboristSite.com Sponsor
anyone prying a saw case apart with screwdrivers needs their hand smacked and tools taken away. its a good way to break or ruin a case.
and if they are at an actual shop.....use their advice as a good indicator to never take anything to them to repair
and if they are at an actual shop.....use their advice as a good indicator to never take anything to them to repair
redhawk23
ArboristSite Operative
I split the case using 20 ounce brass hammer. It worked well once I got the 5th and 6th screw out. Next step is to get the bearing off the shaft and the other out of the case. I am still waiting for the backordered replacement parts.
I’m still curious if anyone thinks a leaking seal alone could be responsible for my initial problem, the saw starting and stopping.
Thanks
I’m still curious if anyone thinks a leaking seal alone could be responsible for my initial problem, the saw starting and stopping.
Thanks
fordf150
ArboristSite.com Sponsor
air leak causes tuning issues and all the problems that go with improper tuning...thats it. stopping and starting is usually a bad ignition coil
redhawk23
ArboristSite Operative
It’s a pretty new coil and I tested it, I believe correctly. I have one of those testers where you can adjust the distance the spark can jump.
