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Datsun 240Z (early series) Mustache Bar Bushing Replacement and Associated Hardware hints.

Recently I undertook the project of replacing my Mustache Bar (MB) Bushings and freshening up the associated mounting hardware. This installation was for STOCK Nissan parts and not URETHANE or POLYURETHANE types which call for several different steps and parts. The step where you remove the actual bushing from the MB is the point of No return, as far as whether to use STOCK or URETHANE bushings. The car that I used for this project has a build date of 6/70 SN 06116: depending on when you car was built the procedures may vary slightly.

This project requires that the car be placed on Jack stands and the raising and lowering of the vehicle. Be careful and follow all safety instructions on your jack, jack stands, service manual and tools. Please use common sense, be patient, and if you have a problem, stop and get some help. Good luck.


Nissan Part # Quantity Required Nomenclature New/Used
55523-E83000 2 Bolt- Rear Suspension Mounting Used
08915-44810 2 Washer- plain Used
Body Of Car
55474-N4300 2 Stopper-Differential Mounting Upper NEW
55476-N4300 2 Insulator-Differential Mounting NEW
55475-N4300 2 Stopper- Differential Mounting Lower NEW
54474-E4100 2 Washer- special Used
08912-84210 2 Nut- Self Locked Used

These are the items you will need listed from top to bottom the way they should be stacked upon completion of the installation.

Removal of Mustache Bar

1. Loosen lug nuts ½ turn on left or right rear wheel.
2. Jack up Car and place on jack stands in a very safe and supportive manner. Your life depends on this step. I prefer to put all four corners on jack stands for ease of accessibility.
3. Remove whichever wheel you loosened the lug nuts on.
4. Place floor jack under differential punkin, just barely contacting.
5. Loosed 17mm nuts that are on the bottom sides of the Mustache bar bushings. (Note: if the bolt turns you can access it from inside the car under strut tower)
6. Remove bushing nuts completely ensuring that floor jack is supporting the weight of the differential.
7. Now there should be some slack between the MB bushings and the mounting point on the car. If not carefully lower the jack so you have about ½ to 1 inch clearance on both sides of the MB where the bushings contact the car.
8. Loosen the 2, 17mm nuts that hold the MB to the rear cover of the differential.
9. If the stud or studs back out of the cover instead of the nuts loosening that is fine, because the studs have to come out anyway.
10. Loosen the nuts until you have about 1 nut width of threads left. Then thread on one of the 17mm nuts you took off the end of the bar to use as jam nut, so you can remove both studs. Note: be very careful here and make sure the MB is not bound on anything that would put pressure on the studs as you remove them. Remember the studs are steel and the differential mounting cover is aluminum and don’t mess the threads up.
11. Now the MB should slide sideways out of the car on whichever side you removed the rear tire from.


1. Clamp the flat of the MB, towards one end into the jaws of a vise.
2. Use special tool, i.e. 1 ½ O.D. piece of steel pipe and a 5 lb hammer to removed the old bushings. There is a lip on the bottom of the bushing so it will have to be taped out from the top.
3. Clean up the inside on mount loop of the MB, and I put a very lite smear of grease on the inside.
4. Turn the MB over in the vise; insert the new bushing with special tool, i.e. 2 ½ in piece of steel pipe and 5lb hammer. Keep the bushing true to the loop in the MB during this step and take your time. Tap into place until the shoulder of the bushing contacts the bar flush around the entire bushing.
5. Repeat steps 1-4 for the other end of the MB.
6. You will notice that the new bushings have taller sidewalls than the O.E. ones. This is necessary to properly install the new bushing. The original bushings were epoxyed into the MB using some kind of space age compound. Soooo, you have to flair the bushing outer casing out and over the lip of the MB loop. Essentially both ends of the bushings should look similar once you are done. The factory did one end now you have to do the other. Once I had the bushings installed I took the MB to a local shop with a press, and they used a hollow cone shaped fixture to start the flair. Next brace the bottom side of the bushing area and use a hammer to tap the lip the rest of the way over. Worked great for me. Some people say to make small serration then tap over. But, I much prefer to roll the lip over as one solid piece.

Installation of Mustache Bar

1. Slide the MB back under and in to the car, remembering the original orientation of bushing loops, mine were to the rear.
2. Stack the hardware and install both ends of the MB putting the nuts on just a few turns.
3. Reinstall the two studs through the center of the MB and into the back of the differential. Studs have different threads on either end. The course threads go into the differential. Be very careful not to cross thread or strip out the case cover at this step. Screw studs in all the way then tighten nuts up. Torque to spec’s, mine was 60 ft lbs.
4. Tighten up the bushing nuts a few turns at a time, alternating sides. Torque to specs, mine again was 60 ft lbs.

The floor jack should be used to support the differential throughout this job to avoid damage to the differential or car, also for additional safety.

Degree of difficulty: 1= put gas in car 10= rebuild transmission, I put this job at a 3.5 on the Z scale.
Estimated time, not counting parts runs or machine shop time. 1.5 hours.
Estimated cost- depends on how good your local Nissan dealer is, mine was about $60.00.
Tools needed:
4- jack stands
1- floor jack
2- 17 mm wrenchs
1- ½ drive ratchet
1- 17 mm deep well ½ drive socket
1- ft lb torque wrench
1- hammer
and assorted special tools (i.e pipe)

Special thanks to:

Virgs Brake and Suspension Shop (machine Shop), Mount Vernon, Washington. 360-336-3673

Gordon Nissan- Parts/Service Department, Burlington, Washington.

Good luck

Son of Z

Email : [email protected]

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648 Posts
Re: Datsun 240Z (early series) Mustache Bar Bush

Excellent write-up! This should go in the articles section of the site.

· Registered
2,284 Posts
Re: Datsun 240Z (early series) Mustache Bar Bush

Hi Son of Z-------------This is an excellent post. IMO, it deserves to be included in the tech articles on this site. Perhaps Vince or Derek can do this?

Gulfport, MS

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39 Posts
Re: Datsun 240Z (early series) Mustache Bar Bush

Son of Z

Thanks for the effort in putting this together - could you add some comments about feel of the car before and after the bushing change - did you notice the diff felt better located etc.


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