Namerow

Interesting. If you look at the consumer-driven stats for the auto industry's products (J.D. Power, Consumer Reports, etc), you find that vehicle reliability has been on a steady and significant improving trend over the past 30 years. Here's an irony for you to consider: Back in the 1960's and 1970's, your vehicle's structure would basically disintegrate after about 5 - 10 years, leaving you with a bunch of perfectly good parts and sub-assemblies attached to an undriveable vehicle. In 2019, the parts and sub-assemblies crap out at the 5 - 10 year point, leaving you with a perfectly good structure that isn't worth keeping because of the uncertain cost and frequency of parts replacements. The vehicle manufacturers are under intense scrutiny over vehicle reliability. For that reason, the vehicle OEM's put their attendant OE systems and parts suppliers under a similar amount of scrutiny. However, the aftermarket parts suppliers are under no scrutiny whatsoever. The only people who tend to know whether a particular repair part (or part manufacturer) is unreliable are the service professionals (who will talk) and the parts supply wholesalers/retailers (who probably won't talk). This because they see such a high volume of incidents. As individual car owner/consumers, we're not in a good position to avoid buying bad stuff. Although it's not a guarantee, I think that the best practice is to stick to well-known brands, even if they cost more (and they almost certainly will). Although many of these manufacturers now have factories in China (and Vietnam, Taiwan, the Philippines, and South Korea), I'm inclined to think that they exercise a higher level of quality control at those plants than would be the case at the generic manufacturers' facilities. Electronics are a special subset of this issue. You can hide a lot of bad quality in 'black box' device without it being evident at the time of installation. Name-brand manufacturers have QA/QC programs and add the cost into their pricing. Generic manufacturers, I suspect, have no such programs.

I had my 70 Z's brake m/c sleeved and rebuilt a couple of years ago at a cost of Cdn $275. A problem I encountered at the time was finding a rebuild kit (the design of the pistons, etc for the early-model m/c is quite different from that used for the later cars). The brake rebuilder that I used operates a big business and has been around for many years, so they had the parts in stock. That was in 2016. Maybe a new stash of rebuild kits has surfaced since then with one of the Z aftermarket suppliers. If not, be sure that you're happy with the condition of your seals and pistons before you invest any time in sleeving the casting.

They're pretty smart when it comes to finding a comfortable place to live...

So you spun up the tube and cut from the inside until the spring perch broke loose? How did you avoid having the perch and the separated part of the tube create a jam when they dropped free?

Side mouldings are gone, too (a good thing). That suggests it's been re-painted.

But PN 55490-E8300 (the weight) doesn't seem to appear in the parts manual. Those add-on rubber washers don't appear to be listed either.

A lot of this discussion about design changes is starting to sound familiar. There's another Topic somewhere from about 2 years ago that has an extended discussion with lots of photos. Re your photo of a car with no lower rubber washers fitted to the MB, it's hard (but not impossible) for me to believe that Nissan would have decided to put the wavy rubber washers on the top rather than the bottom of the MB end mount. After all, the diff weight should be forcing the MB down, not up. That said, I don't understand why the MB bar in the photo is jammed up against underside of the car. Possible answer: The owner used the diff as a jacking point. As a result, the whole diff/MB assembly got pushed up against the wavy washer and got stuck there. Let's assume for the moment that maybe there is only one of these rubber washers fitted at each end of the MB. If that's the case, it makes more sense to put them on the bottom of the mount rather than the top. By the way, that's the way it's depicted in the Parts Manual diagram. What makes more sense to me, though, is that the wavy washers should be fitted to the top and the bottom of the MB end mounts, so that they're put into a slightly pre-loaded state after everything has been tightened up in assembly. In the parts listings, I see four different iterations of the 'Stopper - Differential Mounting'. In every case, the manual specifies 2 uppers and 2 lowers. I don't know exactly what to make of the arrangement shown in your photo. Maybe someone with an unmolested early Z (is there such a thing?) can chime in.

TS71-18 describes a cobbled-up fix that Nissan came up with to address complaints from owners about powertrain noise in Z's with automatic transmissions. It largely consisted of hanging a big-arse weight off the back to the diff casing. It also doubled up on the number of wavy rubber washers at each of the 4 places where these are located. It's interesting to note that the 'teeth' of the new, add-on washers appear to have been designed to interlock with those of the original washers. That would have really stiffened things up. Although I haven't checked the parts manual, I doubt whether this dealership service kit ever made it into actual production. Nissan probably found a more elegant way to solve the problem with the auto-trans Z's (different final drive ratio, maybe?)

As has been pointed out by others, the moustache bar isn't really part of the rear suspension. It's function is to provide a fixed/flexible rear mounting system for the differential. None of the (primary) suspension loads feed through the differential. See diagram below for more understanding. That said, Steve may find this distinction irrelevant to his overall policy of keeping away from parts that he feels may have high potential for liability issues. I guess we'll have to wait to see whether he responds.

A couple of photos, taken by other members, that provide additional illustration of the design and function of these washers...

This snip-out from the 75 280Z FSM provides some insights into what zKars is talking about. The step at the bottom of the tapered-shank bolt limits the amount of crush/preload applied to the wavy washers...

This topic picks up on a mini-conversation that I started on Grannyknot's 280Z build thread. These little washers are an important part of the NVH isolation design for the Z's rear diff. The design, from an engineering perspective, is a lot more sophisticated than meets the eye, so there's an incentive to try to install a proper replacement if your own have deteriorated (which they probably have, if they're 50-year-old originals). Unfortunately, the part is NLA from Nissan and none of the primary Z restoration parts suppliers offer a substitute. There's been some discussion about the need to use vulcanized rubber. I think that's a red herring (look up, 'vulcanized') and was meant to infer that the rubber part needs to be bonded to the metal part. While the originals might have relied on a heat-bonding process, its now 2019 and we have aerospace adhesives for this purpose. So: All we really need is the rubber part. Steve / Nix240 has cobbledup a wide range of rpreviously unavailable rubber parts for our Z's. I see nothing special about re-creating the moustache bar runner washers, other than using a suitable durometer rubber and having access to a good-condition original to create a mold. After that, they could be bonder to a suitable metal washer and, presto, we have another part taken off the NLA list. I think these washers carry across the entire 240-26-280 series without any differences. Maybe even the ZX's? Also: I'm thinking that the same might be the case for the Series 1's diff front insulator. Steve creates the rubber piece, then the owner carves the perished rubber out of his insulator, cleans up the metal armature, and then bonds in the new rubber. @nix240z Steve: What do you think?

So as not to hijack Grannyknot's build thread, I'm going to start a new topic about the moustache bar bushings.

For another view of fast driving on Irish roads, check out some of the videos available online of the 1950's-era Dunrod Tourist Trophy race. At the time, the drivers (Stirling Moss, Mike Hawthorne, etc) considered it on par for difficulty with the two better-known open-road races, Targa Florio and Mille Miglia. Dunrod was discontinued after a single accident at a blind brow killed two drivers and wrote off three cars. If you're thinking about taking a vacation in Ireland, you should be aware of one important fact: It rains a lot (so more pub time). Other than that, I highly recommend it as a destination. When I was there, I drove the south coast road and used the town of Dingle (south-west tip of the island) as my base.

Are those new mustache bar mount bushings (the serrated ones)? If they are, where did you find them?