"What is the procedure
and advantages of coverting early Morgans from
front drum brakes to
front disc brakes?"
| MILES | RUTTER | SHEALLY | SOLOW | WILLBURN |
Michael Miles (special from the eMog Pub)
Line-boring the bushings should yield very good results. Just like the machining of the bearing journals for the TR camshaft or for crankshafts, it results in the best alignment of the cylindrical faces. Honing to final clearance would assure you of uniform fit. Simple reaming is subject to the reamer re-centering on the workpiece and flex in the reamer shank leading to some drift.
A nominal clearance of 0.005" is on the high end for an ANSI RC-7 'free' running fit (0.0025" to 0.0057"). Medium sliding fits (RC-5 and RC-6) range from 0.0016" to 0.0036" and 0.0016" to 0.0048" respectively. These vary because of different tolerances for the shaft as opposed to the bushing.
More than you might have cared to know but I can easily believe that given variances in reaming, allowing a looser fit in years gone by was far more practical. Something requiring the skills readily available at the corner mechanics shop to get back on the road.
With the ability now to machine more precisely, the system
should be able to work more precisely. How
much is enough is a whole new question of course.
Just because we can doesn't mean we should.
Practicality must prevail at some point (momentarily
recalling Peter Ustinov and the Grand Prix of
Gibralter).
Mike M
In response: As your bushes have already been fitted
and now reamed out, you can do no more. An alternative prior to fitting
bushes would be to have machined three grooves on the inside, with a "lead
in" vertical groove to allow the passage of grease. You can still do away
with the one shot oiler and fit grease nipples to the top
.
Best wishes, Melvyn R.
Dear Crazy Horse,
I have always used the standard factory Kingpins and bushings
with a .005 reamed clearance. I then pack white moly in between the upper
and lower bushings then coat the kingpin with same and insert. At that
point it is done and I am good for 90 to 100,000 miles.
This has worked for me over and over. I also cut one and one half coils
off of the rebound spring as to give movement to the king pin movement
as the rebound spring at full lenght is coil bound and is usually taken
out in pieces upon replacement of kingpins and bushings. The factory is
at present useing a composite material bushing in place of the bronze ones
which I have not as yet used.
Best to you, John H. Sheally II
With only .001" clearance the front suspension will not move freely. The kingpin and /or the spindle assembly flex enough under the wieght of a +4 or a +8 to sieze and not move if there is any less than .005" clearance. With .003" clearance, a +8 suspension will not move up and down with the weight of the car on the suspension. We set them up with a hone to .005" and don't bother with any grooves, they are not necessary. The .005" clearance is enough to allow the grease to fully lubricate the bushings. We also recomend not using the oiler. We recommend greasing the kingpins every 1,500 miles.
Regards, Greg Solow
Hi Lorne,
We ream them to "feel" (0.005" wrist?) and DO use the oiler. We also like to install an "O" ring at the bottom to keep the dirt out and the oil in. .
Gerry