Idler box question

[dbrick]

I picked up a very nice replacment idler box assy, the one on the car is loose. It's the late type. is there a spec how far the shaft gets screwed down into the housing? When I run it all the way down and then back up a turn, the 2 grease seals(?) are an inch away from the bottom of the housing and the threaded part of the shaft is almost all the way down inside the bushing on top of the housing. The one in the car has an 3/4 to 1 inch of threaded shaft showing above the housing, (under the rubber cap). I can't find any info.

Also, is this part as difficult to change as it looks?? I wish I knew it was bad while the engine and radiator were removed .

Any help, even creative guesses, appreciated.

[dbrick]

I'm suprised, not even 1 opinion?

[datsunrides]

I can't speak for the later style, but I just reinstalled an early model box on my frame. I referenced it before I took it of to clean and paint it. Mine had the large washer basically flush with the top of the housing in the center position. Another thing I noticed was where you set the shaft will affect the how tight the seal ( between the box and arm ) will be. Obviously you would want to set it so it's tight enough to keep the grease in but not so tight that it will rub on the box and shred itself. As far as removing it, you probably will have to pull the arm off the box before removing it. I put mine on a bare frame and could not get it in as one piece but I also was trying not to scratch / chip my fresh paint job! Plus if you do it this way, you avoid having to break loose the inner tie rod. (If I remember, these are a *#$@%$). Hope this helps for your application.

Mark

[itsa68]

A kick at the cat.

On the upper part of the arm, there is a bump stop about an inch long and has a flat surface on it.
Space for the nominal seal thickness should be maintained when the flat surface of the upper arm is aligned with the mounting base vertical machined flat surface.
The upper arm will be facing forward (towards front of car) when the surfaces are aligned.

Using a vernier caliper, measure the larger diameter of the tapered shaft hole in the arm.
Lock the caliper jaws at the measured diameter and slide the shaft between the jaws until the shaft diameter matches.
Mark the shaft at this position using a fine tipped felt pen to indicate where the arm diameter would bottom out on the shaft when installed.
(If you don’t have a caliper, you also might be able to visually set the jaws of a crescent wrench to the arms large diameter and transfer and a mark to the shaft in the same matter.)

Slide the seal onto the shaft and make a second mark to represent the seal thickness.

Remove seal and install shaft to housing.

Lower or raise shaft in housing until the seal thickness mark aligns to bottom face of the housing.

The shaft end should be now be protruding from the top of the housing at approximately .640� (162mm) and the step on the shaft to housing top at .320� (81mm).
(I wonder if they used that step as a 2x guide for the assemblers?….I’ll have to check that out )

Install the lower seal on without moving the shaft.

If bench installing he arm, use a 2x4 on edge and place the housing machined face on it to aid you in aligning the housing to upper arm surfaces noted above in the first paragraph.

Slide on arm to **maintain alignment surfaces** by only rotating shaft a minimal amount to engage on the shaft spline keys.

Hand tighten arm to shaft and check seal compression/decompression before final tightening.

Please note the dimensions I mentioned are only to be used as a guide and were obtained from an existing unit and others may vary.

Ray B.

[dbrick]

That is one hurting cat!! So it's a very simple procedure
I guess the first step is to see how tight the bushings are in approximate installed position, about 1/2 inch higher than it is all the way in. Is there any sort of rubber seal at the top besides the rubber dust cap? All the grease seems to go out the top and not get to the bottom bushing.

Does this sound over simplistic....

Screw the shaft all the way in, back out 1 turn put on rubber seal then 2 stainless washers, put on a strong coil spring to hold the seal in place and reinstall arm.

[itsa68]

I can't comment on that one.
That might possibly interfere with some other geometry.

Ray B.