Donald,
Before proceeding further, ask yourself these questions:
1. What kind of an owner/mechanic would put spacers on the main
landing gear oleos without servicing the oleos?
2. What kind of mechanic would sign off an annual without inspecting
the main landing gear oleos for proper fluid and operation?
3. What was the date of the last annual on this bird?
4. How long does it take to eject or evaporate fluid from the MLG
oleos and then for them to seize from rust? (Hint...a lot longer than
a year!)
These questions should suggest to you that prior maintenance of your
airplane has been questionable, at best. That, to me, puts associated
paperwork in question as to completeness and accuracy. It might be
prudent (regardless of your finances and personal skills) to find and
hire a competent mechanic to oversee a progressive annual on it as soon
as possible.
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What follows is ONLY applicable to Serial numbers 813 and up!
"Pounding and beating" with a "LOT BIGGER" hammer is a traditional
practice of blacksmiths, but such skills of that honorable trade have
little application to proper repair and/or maintenance practices on an
Ercoupe. Unnecessary damage is the likely result.
The same is true (perhaps even more so!) with regard to using a torch
on any part or assembly in or on an airplane. It is so seldom
necessary as to be best left to an expert. Dismounted, in the vise, OK
(with due care). Remember that any brake fluid or hydraulic oil
remaining in an oleo will likely boil out or vaporize given sufficient
heat, with unpredictable and possibly dangerous result.
With reference to the Parts Manual, Fig. 12, to get the oleos off the
plane you need to remove Items 27, 28 and 29. Before proceeding,
liberally soak them with good penetrating oil. There are times when
only force will resolve a problem, but you want to think everything
through so as to reduce that force to the absolute minimum necessary
before proceeding.
It is unlikely Items 27, 28 and 29 are frozen; but if they are, the
shock of periodic light but solid hammer blows assist the lubricant to
penetrate the assembly. Apply with a punch of slightly smaller
diameter to the bolt threaded end (if that is accessible) or any large
flat-ended punch to the rounded "screwdriver end" (apply so as to not
bugger the screwdriver slot).
If the cotter cannot be extracted in the normal manner, cut off the
bent ends of the cotter. Lock a Vise grip onto the loop end and try to
pry out. If still unsuccessful, try to rotate the nut/bolt such that
the cotter hole is vertical. If you can't, cut the loop part of the
cotter off with a sharp chisel (flush with the nut and use a socket to
to rotate the nut/bolt such that the cotter hole is vertical. Then use
a pin punch to drive out the remains of the cotter.
If it is not then possible to simply remove the nut with the
appropriate wrench, cut the sucker off with a chisel and drive the bolt
out. Replace any part not in perfect condition after removal (for
reasons that should be obvious), and never reuse a cotter pin.
Once the whole oleo is off the plane, position it in the same
orientation it was mounted and squirt penetrating oil into the filler
cap and the upper seam between cylinder and piston every day (several
times) for a week. (Yes, you could have started this soaking while
getting the assembly off the plane ;<) Then (and ONLY then) attempt
to disassemble each oleo. As Paul pointed out, it may be that your
oleos cannot be saved; but I would try.
Position the rubber donut stack securely in a large, well mounted vise
so it is not easily dislodged. You DON'T want to apply force to the
"ears" the mounting bolts go through and you DON'T want such clamping
force applied to any unsupported part of the actual cylinder in which
the piston must travel freely as permanent distortion will likely
result.
Using two pipe wrenches of appropriate size and cloth padded jaws to
clamp on (1) the flange of the attaching end of the piston (supporting
the "ears" through which the mounting bolts go) and (2) the flange on
the oleo cylinder supporting the rubber donut stack (perhaps with a
friend's help) apply rotational force (as if unscrewing a nut from a
bolt) so as to break the piston-cylinder seizure. This MAY distort the
bottom donut spacer, see item #20, Fig. 12 in the Parts Catalog (if so,
and it cannot be straightened, replace it).
If unsuccessful, try adding torch heat to the (lower) cylinder (where
you can get to it). If a little isn't enough, add a little more. Any
expansion is a good thing, although transient. More than is absolutely
needed is too much. Again, this is no place for the blacksmith
approach of heating things to different colors! DO NOT apply heat to
the (upper) piston. Expansion there works against you.
If still unsuccessful, "overhaul" your Belleville strut assemblies.
Most cylinders will benefit from cleaning and honing, and pistons from
cleaning and flushing out with acetone. Degrease, prime, paint and
lubricate parts as appropriate before reassembly. A coating of STP for
the upper and lower mounting bolts (and threads thereon) in the process
of assembly could reduce wear and eliminate all possibility of seizure
here in the future. STP is a rifle, not a shotgun. In many places it
has properties you DON'T WANT "in play".
Remember, I'm NOT a mechanic. but can do such work "under appropriate
supervision" (as can you).
Regards,
William R. Bayne
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(Copyright 2010)
--
On May 23, 2010, at 16:20, Donald wrote:
Fitting in with the MLG postings of late, I decidewd to jack mine up
and put in the spacers to raise my tail today. As I was taking thinga
apart, I was surprised to see there were already a set of spacers
there. Strange, my tail is pretty low.
I decided to measure my donut stack, three and 1/2 inches, although
the rubbers look as good as new. I jacked it up to measure again no
load - still three and a half! What the heck is going on here. I
have a pair of bellville spring equipped struts, measured them, and
the stack is about four and a quarter inches!
I decide to take things apart to see what is going on, drop the bottom
bolt, swing the strut back to pull it off - and it won't move! Now I
understand why the rubbers are compressed - the strut is froze solid
in a compressed state! Take the other side off, same thing.
Easy, just pull the top bolt out - whoops, I think you must have to
pull the wings to do that AND have some special wrenches, not what I
wanted. I found I could put a drift down thru between the wing and
center section, and pound on the top of the strut to try to beat the
bottom part off. No luck, gave up for the day and came home to get a
bigger hammer - a LOT BIGGER hammer. I may have to heat the outside
of the strut to release it, probably burn up the rubbers, and I don't
even know for sure WHERE the sticking is!
Has anybody else had this problem? I could sure use an easy solution
right now.
No wonder I had such a devil of a time with smooth landings, darned
thing had NO spring action whatever!
