Rear Shock Top Mounting – clunking

[Casey]

Driving back from The Retro Rides Gathering recently, a “clunking” developed, which appeared to be coming from the rear nearside. It only occurred on bad road surfaces, no problem on a smooth road. I stopped the car and did a quick check that nothing was obviously loose or broken (I couldn't see/feel anything) and drove carefully home for the last 30 miles.

I've had the chance to take a better look today and I'm 95% sure it's the rod in the rear n/s shock rod that is banging against the side of the top mounting hole (diagram from Haynes manual):

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The grommet shown in the diagram has all but disintegrated (light brown item in pic below), so allowing some sideways movement:

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The shock itself, although manky, still appears OK, albeit the bottom bush is showing some signs of age. I’m torn between cleaning it up, sorting out the “grommet” and putting it back on. I’m thinking I might put an “O” ring or two in place of the grommet?

Alternatively, I have a pair of brand new KYB shocks that are meant for KIMI 1, so reluctant to use those in case I have trouble sourcing another pair. Also, here is a picture of the KYB shock and fixings, but it doesn’t include a grommet either?

2016-09-05 12.36.57.jpg (107.18 KiB) Viewed 2776 times

Has anyone got any thoughts before I put things back together?

[MelloYello]

I am sure some generic replacement from eBay would do the trick.

[DKWW2000]

I changed mine about a year ago with new KYB, I seem to recall my new rubber bushes were similar to the drop link bushes & had a thin lip on one surface which I fitted against the chassis.
I have some old Drop link bushes I could send if you needed them as they are similar?

I used them cut down when I fitted the Front Strut inserts as they rattled in the strut & I also used some thick 'O' rings

[Boggy2112]

I have just striped a old fb, i am sure i have the rubbers if you need them!

[TOOL]

See if you can get a generic grommet, like the ones on the firewall stopping the loom getting cut. That should go it.

Never seen grommets used on shocks before.

[kenwhiteside]

I got a pair of those shocks for just over 20usd from rock auto a few weeks ago. Have a look there.

[Casey]

Thanks for the replies guys. I looked around in my spares bin and found some rubber parts that are perfect to replace the grommets! The shocks look in good shape, no leaks, and they appear to work fine, so I've now taken both shocks off KIMI 2 (and yes, the grommet in the 2nd shock was also in bad shape, no surprise there!).

I've now degreased both shocks, metal prepped them and put on 2 coats of Black POR15. I've left them to cure/dry overnight and will hopefully get them back on the car tomorrow. I'll post up some pics in my KIMI 2 thread later for the record

BTW, does anyone know the difference between these two KYB rear shock types:

KYB 343140
KYB 343064

I have a pair of the latter ready to go onto KIMI 1, but the 343140 is showing as the p/n on RockAuto for the 1979-85 RX-7?

[KiwiDave]

BTW, does anyone know the difference between these two KYB rear shock types:

KYB 343140
KYB 343064

I have a pair of the latter ready to go onto KIMI 1, but the 343140 is showing as the p/n on RockAuto for the 1979-85 RX-7?

Both part numbers appear to refer back to the ExcelG. For the US market, KYB dropped the ExcelG label and reintroduced them as GR2. The rear shocks were the same fitment '79 thru '85 whereas the fronts differed. Series One fitment was unique (taller). S2/S3 were the same.

[Casey]

Thanks Dave - they appear to be physically identical to the S2 shock I removed, so hopefully OK when I come to fit them to KIMI 1

[Casey]

Shocks immediately after removal, covered in grease by the previous owner, in an attempt to ward off tin worm...

2016-09-12 12.14.17.jpg (78.27 KiB) Viewed 2776 times

Degreased, ready for acid etch and POR15...

2016-09-12 15.03.30.jpg (71.95 KiB) Viewed 2776 times

2 coats of POR15, a little better...

2016-09-13 16.13.47.jpg (96.19 KiB) Viewed 2776 times

Fitted, the cleanest bit under there!

2016-09-13 16.51.08.jpg (105.06 KiB) Viewed 2776 times

These are the two "washers/grommets" I made from a rubber cap I had lying around...

2016-09-13 16.32.22.jpg (124.45 KiB) Viewed 2776 times

Fitted into the gap a treat - a tight fit over the damper rod too...

2016-09-13 16.34.04.jpg (157.93 KiB) Viewed 2776 times

The bad news is, I still have the clunking sound - more diagnosis required....