Mike,

When I did this same replacement I do remember that the reel and cover
did need a bit of fussing to get them correct. As I recall, I may have
bored out the mounting hole to get the units to install flatter against
the fuselage. Once done, the covers would fit with just a little tension
(not enough to bind the belt operation). Before the mod, the covers
would bind the belt as you said.

It has been a while so I am not exactly remembering what I did. But I do
seem to recall that the metal base of the new units were a smidge "off"
from the originals and I do recall boring out the big mounting hole. I
may have actually bored a new hole next to it. I recall the base plate
would ride up on one of the reinforcing ribs (or something like that)
and making the hole a bit bigger (or relocating it a bit) made it
possible for the unit to JUST clear the rib.

Anyway, your solution appears to also work without tampering with the
unit. If I recall, the headliner rides about 1/2 inch away from where
the mounting screws and cover will "bottom". Using spacers to hold off
the cover should leave no gap because the headliner will "fill in" any
gap (up to about 1/2inch). You just have to make the holes in the
headliner big enough to clear the spacer diameters.

Good info. Thanks for posting.

Mike

wrote:
There was a thread a few months ago on this topic. After seeing that
information, a friend of mine installed a $150 inertial reel from
Chief aircraft in a PA28-180 as a replacement for one that had frayed
and stretched and was not retracting well.

Overall the installation went well and the shoulder belt works as it
should. The mechanism was a bit larger than the original inertial
reel so the plastic cover over the reel had to be shimmed away from
the cabin wall about 1/8' to maintain clearance from the reel. This
was done with nylon tube spacers and longer cover mounting screws.
He's happy with the results.

The co-pilot shoulder belt was also not keeping tension. He noticed
it worked well with the plastic cover removed but not when the cover
was in place. That belt is now also keeping tension after he spaced
the cover about 1/8' away from the reel.

The other problem he had was the shoulder belts not attaching securely
to the mushroom on the lap belt. He cut short lengths of silicone
rubber tubing (available in hobby shops as fuel line for model
engines) and pushed them onto the mushrooms as friction bearings. Now
the shoulder harnesses attach to the lap belts securely.