"I have reamed my bushings to a  .001 inch clearance now I am wondering about  scoring each bushing lengthwise to allow better passage of grease the length of the bushing."

GOMOG Note: You will almost certainly have issues with a .001 clearance. It is nopt enough that the kingpin can slip through the bushes on the work bench. It must be able to do so when the pressures of a flexing frame and torque are present as well. Try .004".

Obviously, it would be easier on owners for the factory to precision machine the stub axles tubes to a standard. That would make the correct bushes a resultant fit..needing only to be pressed in to have the right kingpin clearance, as the DEVOL cars were. But the Factory decided against this simple benefit, hoping to give British dealers regular work. S'truth as I have been told.


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  uch is enough is a whole new question of course.  Just because we can doesn't mean we should. racticality must prevail at some point (momentarily recalling Peter Ustinov and the Grand Prix of Gibralter).

Mike M

Melvyn Rutter

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.

John Sheally II

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  oint 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 using a composite material (DEVOL)  bushing in place of the bronze ones which I have not as yet used.

Best to you, John H. Sheally II

Greg Solow

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

Gerry Willburn

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.  .