I have the Showa Bathurst coil overs on my FD, these use the stock Mazda shock absorber upper hats with a height-adjustable shock body. It seems that the shock bumper inserts (kind of a yellow color foam) are degraded and basically falling apart. The shock uppers themselves are in perfect condition otherwise, just the bumper material is bad. I am wondering how important this travel limit bumper is for a street driven car, or if there might be a replacement part available. For now I just cleaned out the crumbling inserts. If anybody has info on replacements I'd appreciate it. Shocks are in perfect shape otherwise, so I'd like to keep using them as they are a great street shock absorber albeit a real pain if height adjustment is needed.

 

That is typically referred to as a bump stop.
The stock Mazda upper shock mounts typically have a hard rubber bump stop. It is removable with some effort. If yours have a foam style bump stop as you make it sound, it very well may be aftermarket unless it came with the coilovers.
I'd recommend measuring the length and attempting to find a similarly sized aftermarket bump stop and trim to fit.
When I did my custom valved Fat Cat coilover setup I wound up using Miata bump stops and trimming to fit. 5xracing took over the Fat Cat bump stop business. Here are the various bump stops they offer:
https://5xracing.com/c-1231774-na-mi...-hardware.html

Some pics and info in my suspension thread: https://www.rx7club.com/suspension-w...setup-1104755/

You may be able to find similar elsewhere.

 

Thanks for the link! Yes what I am asking about is the bump stop. It's hard to know the density of the existing bump stops as they are disintegrating into crumbs kind of like what happens to poly engine mounts. The material is yellow/orange in color, probably was originally ~1 inch in height but it's hard to know for sure since they are falling apart. I'll look into the offerings at 5xracing.

 

More important than on tracks.....they don't tend to have potholes, spoon drains and speed bumps there! Stock FDs tend to ride the bumpstops, particularly in the rear, you run the risk of internal damage without them. Bilstein, etc, would have a nicer riding foam stop that should fit.

 

I had the exact same issue on mine. As far as i found there are two options:
- Use some other bumpstops, from say a MX-5
- Buy new top hats that have them integrated like on the OEM suspension. (they only cost 20-30 USD more than the bumpstops xD)

I went for the later option. The original parts for the Showa Bathurst are not available anymore.

 

Here's what came out of my dust boots when I took my struts off. This stuff is like sticky cake and is a pain to clean up if you accidentally smash it. I guess this is what the bump stop turns into after 31 years. I tried buying new upper seats but the list price is pretty expensive ($132/each). I found two on Ebay listed for ~$15 (plus shipping) from different vendors so I ordered them, but one order was oddly cancelled and they did not reply to my message asking why. I am really annoyed because the rest listed either come in pairs from Japan for ~$250 or from Canada with extra shipping and import tax which comes out to $100.
I am tempted just to buy some coilovers, but my car is "preservation status" so I need to keep it stock or return it to stock when I decide to offload my "investment". So I'll have to bite the bullet and buy the stock parts at some point.

@Zepticon Are you saying the MX-5 bump stops fit from the same era (NA)? I guess any bump stop would do the job as long it fits around the strut piston and not around the chamber. This stuff seems to be glued to the upper seat though within the dust boot. I didn't take the spring off the strut to actually see what's inside the dust boot, but I stuck my hand in there to scrape out any loose chunks of the stuff. Not sure if you can just take it all apart and clean it out and then shove a Miata stopper on the piston, but seems possible. Would like to get someone's take who has done this before disassembling more stuff.

 

The oem FD ones are full one-piece construction with the bump stops integrated in the spring seat and shock protection sleeve. Seems bad to replace everything just for broken bump stops so thats why i suggested the MX5 ones. I have not done any testing tho, but for $15 it might be worth a shot.
Mine looked just like that when i refurbished the oem Showa coilovers from the bathurst version.

 

@jdwk post a pic of the upper shock mount and dust boots. That red stuff does not look oem.

 

I didn't take the spring off the strut, and couldn't get a shot of the crud down in the dust boot. The one OEM part that shipped should be here tomorrow which will confirm what material the OEM bump stop is.



The reason I took the struts off was to diagnose an annoying squeak coming from the rear suspension over bumps. It sounded like it was coming from the upper end of the struts when I push down on the rear end but it's really hard to pinpoint noises like that. It is probably the control arm bushings and the sound just traveled up the suspension. I guess that will be my next purchase/install.

 

OEM bump stop is rubber as you can see from the pics in the link I posted early in the thread. Whoever did the shocks on that car probably used some sort of aftermarket bump stop that got pummeled to death because there was no room for it (if they kept the OE bump stop) or it was too long - unless they removed the OE bump stop and replaced it with an aftermarket foam / urethane bump stop like I did in the mentioned thread.

The annoying squeak could be from the lack of a thin plastic sheet between the upper shock mount and the unibody. It the white plastic sheet in the pics here: https://www.rx7club.com/suspension-w...m_content=post
Or it could be something else...

 

My bone stock unmolested Showa coilovers with 4000km on them according to seller also had this foam thing on them that was like wet cake when it came of.

 

Yeah my first suspicion was that whoever installed the struts (a friend of the previous owner who is a BMW mechanic) forgot that plastic sheet and why I took them off in the first place, but the plastic was still there on both sides. I used white lithium on all the exposed rubber and put the rear struts back in and the rear end is a lot quieter, but it's still not totally quiet, and the front end still needs attention as well. Not sure if it is worth buying and replacing all the control/"I"/trailing bushings for a minor squeak though. Those bushings aren't cheap and a pain to replace without the proper SSTs and an actual press, so I think I'd only want to replace them if it is really needed.

My replacement "new" OEM bump stop actually came today, and it is definitely the stuff that turned into the wet cake. Either Mazda changed their supplier at some point, or your OEM parts weren't actually OEM but an improved reproduction. I would much rather have your rubber ones than these ones that will eventually turn into wet cake again. If you have the receipt for them, or remember where you ended up purchasing them from, that would be really great. This was also the only cheap one on Ebay, the rest are over $100.




My next mystery to solve is my front end. Not only is it noisy, but it is much lower than a stock car would be, and only the struts were replaced in 2015. So how do you lower a car with non-adjustable Koni Yellow Sport struts and the stock springs? There is a physical gap between the strut tower and the rubber stopper at the top of the strut. I'm gonna have to take it apart to find out, but I think my wife wants here garage spot back so that might have to wait until I have more garage space.

 

That's surprising. The red, apparently foam bump stop was not present in the OEM upper shock mounts that I sourced from Ray Crowe - pics in my old, linked thread. It wasn't present in the shock mounts that I was replacing either. I wonder if there was a part change sometime along the way. The red foam bump stop is probably better than the hard rubber bump stop in the mounts I have. Yeah, it degrades / wears over time but should provide better ride quality.

Regarding the gap between the shock tower and that isolator thingy, you'll have to disassemble the shock spring assembly and check if there is a spacer sitting there causing the gap. Could also be caused by plain old wear of the shock mount.

What year are your cars @Zepticon and @jdwk

 

I got the showa coils from Yahoo.jp so i am not sure of the year, but they where in mint condition. The seller wrote it was removed from the car at 4000km and then put in to storage. The condition supports that. Then i got another pair that was is similar condition but with less info.
I got both pairs somewhere in the attic, but a bit much work to dig them out and check. One is 100% stock the other with replaced rubbers since it was falling apart.

 

@gracer7-rx7 My car is a '94. The tag on the bag has a 2017 date, but who knows when it was manufactured and how long I have before this bump stop will turn to mush. The foam seems fine right now, but the rubber definitely doesn't look new. The vendor that canceled my order did finally reply and said that the part is on backorder until April. Does that mean Mazda is making more? I read that they are offering a restoration program for the FD like they did for the NA. Unfortunately, it is only for Japan, but maybe we'll be able to buy the parts.

As for the gap on the front strut, I believe a pancaked rubber shock mount is the only thing that would both lower the car and create that gap. Unless I am visualizing this wrong, the spacer raises the nuts and the rubber stopper from the mount, but it wouldn't affect the ride height. I am fairly certain the spacer was on the rear struts, so I would expect it to be used on the front as well. It is clearly depicted in the shop manual, but maybe you are supposed to remove it when installing the front Konis and not the rears?

I was suspicious that the front struts were just the wrong part so I just took the wheel off and the part numbers are correct. I also shoved my hand up under the boot and there is no foam on the fronts. The fronts are just like those in your old thread where it is all just one rubber piece. @Zepticon was the wet cake only on your rears?
I may take the front struts out tomorrow, but seems like a lot of work if the conclusion is "that's just how the front Konis sit". I actually like where the ride height is now, I just want to try to tackle some of these noises, and that gap looks like it might be a culprit.

 

To be honest i dont remember. I will check the one i have if i remember it this weekend. Need to get up there and find the holidaystuffs in any case so might as well have a peek in the box

 

Thanks. Yeah my next door neighbor already has their house and lawn decorated, so I'll have to pull out my lights now too so I don't look like Scrooge. I thought we were supposed to wait until Thanksgiving.

 

I was cleaning out my garage a little bit and found a bag full of lug nuts from either my MX-6 or my MSP and there were also some bump stops in the bag. They were a yellow material but also crumbled into that sticky cake like substance when I pulled them out of the bag, if they were from the MX-6, then they would be about the same age as the ones on the FD.