"Normal" vs. "Hard" Shock Absorbers
 

In July 2008 I replaced the RF shock on our '94 FD at 95859 miles, due to a fluid leak.
I also replaced the LF shock (at 96044 miles, on general principles).

In June 2010 I replaced both rear shocks at 101510 miles, again "just because."

All four shock absorbers were intended as, ordered as, invoiced as, and labeled with, the "Normal" suspension part numbers, not the "Hard" suspension part numbers, which differ from the normal P/Ns by only one digit.

However, since replacing the original shocks, the ride is much harder, to the extent that for instance on I-5 in L.A., we are severely spanked by road roughness. Driving over that same highway in our Ford Fusion, the road actually feels smooth.

Now I know folks will say "Hey, it's not a luxury car," etc. but we bought the car new and have almost 100K miles experience with it before putting these shocks on, and it was not anywhere near this rough.

Either the shocks were mislabeled, or somehow (unlikely) the suspension has seized up to the point that we have a "little red wagon." (The front shocks were bought from Huntington Beach Mazda, the rear ones from Ray at Malloy Mazda. Problem seems overall, not just front or rear.)

Since the car has 107.5K miles on it currently, we have only about 6K miles of experience with these shocks. Originally I thought they needed "breaking in," but I am no longer giving them the benefit of that doubt.

Any comments would be appreciated... any experiences? Thanks!

you sure you installed them correctly ? preload and such ?

As I recall, the 93 shocks were stiffer than the 94's. Did you order the 94 replacements? It may also be true that your original shocks were stiffer than you remember, and they may have softened up after a few years of driving. It has been nearly 20 years since you bought the car.

Check the part numbers. Maybe they sent you the wrong ones.

I just removed my 94 shocks with 71k on them. The front was lifting upon acceleration, and the car was feeling more floaty at higher speeds than it used to. The shocks seemed to be ok when I removed them. I think they got softer since I bought the car in 2002 (42K miles).

Probably not. I have no idea how you preload a shock absorber. I just installed them and drove the car. They went in perfectly. I also replaced the bumper stops and other ancillary stuff with new parts. Picked the numbers from the '94 parts catalog. Part numbers on shocks and on the invoices are what I ordered:
Right front: FD15-34-700A
Left front: FD15-34-900A
Rear: FD15-28-700A

Above are the P/Ns for the "Normal" shocks, which I ordered. The "Hard suspension" shocks are:

Right front: FD16-34-700A
Left front: FD16-34-900A
Rear: FD16-28-700A

I'm thinking that maybe the FD15 labels were mistakenly put on FD16 parts... I have no idea how to prove or disprove that. Also I have no '93 FD parts catalog, so cannot find whether the part numbers are different between '93 and '94.

Checked a '93 FD parts catalog and found that the P/Ns are different; same idea with "Normal" and "Hard" suspension shocks, except the "Normal" PNs begin with "FD01-" and the "Hard" P/Ns begin with "FD03-." Would guess the physical configurations differ from the '94s.

(Also looked at a '95 FD parts catalog; rear shocks are the same as for the '94, but front shock "Normal" type is a "FD123-" whereas "Hard" type is still same as '94 "Hard" type.)

There is no pre-load or other adjustment on a stock shock absorber for these cars. So, it's pretty much remove, install, and drive. Good call on new bump stops and other rubber bits.

I though shocks were all the same thru the few years, guess I still have things to learn. Or, it could just be Mazda's numbering, as aftermarket shocks (such as my Koni's) are the same for 93-95.

OEM's change more often than aftermarket. Larger quantity to amortize costs over.
As to Mazda PN's FDxx is the model series number of the car so 01 is 1st series, 03 the R 1, 15 US 1994' 16 the R2 numbers go to 176 or so covering models, years til end in 2002.
As to OP,s question, a 100k shock is worn out and approaching 20 years old, regardless of what you think or feel. They degrade slowly unless a seal blows; us just don't remember what the car or you used to feel like when you too were young.

Hate to belabor my original point, but this car is still riding like a "little red wagon" at 116K miles. I have never read (on this forum) complaints about any of the U.S. FDs riding very hard. But as a comparison, I have ridden in a Morgan Plus 4, Datsun 1600 SPL-311 roadster, Fiat X1/9, and 1990 Miata (owned the last three), and they all rode much more smoothly than our '94 FD does since my replacements.

Does anyone have any further comments? Like, has anyone replaced their shocks with OEM "Normal" types and found that the ride is MUCH harder?

Your '94 part numbers are correct, so if those are on your car it should ride like my "normal" '94 base model, unless the parts were incorrectly numbered. That seems unlikely, but not impossible. When I bought mine in 1994 I also test drove the '94 R2 and found its suspension too harsh in comparison for use as a daily driver. Even so, my base model is still pretty firm -- stiffer than most cars.

By any chance did you also change tires when you changed shocks?

I can tell you that on my '95 with 50k miles and non hard suspension, the ride was maybe not rough, but certainly stiff enough for the street. It wasn't as stiff as my '05 CTS-V, but definitely stiffer than my 2015 Mustang with non hard suspension. Having a low mileage stock car reminded me that these cars in factory form (not even R1/R2 trim) were actually pretty hardcore by today's standards. The ride was stiffer than my mustang, the clutch stiffer than my Challenger with 5.7 V8, that kind of thing.

What other cars do you own? You may be used to their ride quality and now feel a contrast.

The other thing that sucks is that if you have beat up roads, it can unsettle the car in turns. It's one reason why harder suspension may not handle as well on the street as you would expect it to - it's meant for better maintained roads.

It's hard to say exactly, there may be a combination of things going on here. Mazda may have revised the shocks over time to make them stiffer or just simply got rid of the normal/hard and made all of them the hard suspension valving. That's very hard to tell.

It is also true that shocks will wear as time goes on - they may not leak externally, but they may not perform the way they used to.

It may be one, it may be the other, it may be a little of A and a little of B.

If you have the time and desire you can find a shop that has a shock dyne and put the old and new shocks through it to see what the comparison is.

Also the FD's shock design is a 30-year-old design, suspension tech has come a LONG way. If you want to get your car riding more smoothly take a look at my "Old man suspension" thread. Going with a Tein Flex Z or some other alternative can get you a good, comfortable ride that will handle well. You can also put the car at near-stock ride height, you don't necessarily have to drop it when you install coil overs.

Dale

That has been and is my current guess; the "Normal" part number labels got slapped on "Hard" shocks and sold to the customer. But maybe not... who knows?

[QUOTE=Mazda may have revised the shocks over time to make them stiffer or just simply got rid of the normal/hard and made all of them the hard suspension valving. That's very hard to tell.[/QUOTE]

That would be my second guess. Is there any way to see a physical difference, like engraving or such on a "normal" shock that might not be on a "hard" shock? I've never heard of a "shock dyne," and I don't have the originals.

I guess another possibility could be binding in the rear suspension making it appear harder, but cannot see why that would have happened at exactly the same time as the shock replacements. And the problem seems to be at all four wheels. Thanks for all your replies!

After you inspect the suspension to make sure the it is not binding and the shocks were correctly installed, you could call or email Ray Crowe and ask him if he knows whether Mazda changed the normal shock valving over time or might have mislabeled them.

Shouldn't make a huge difference, everything torqued up at ride height back when?

BTW, that should have been "shock dyno" - it's literally a dyno for shocks. It grabs the rod and cycles it up and down and you get a report out of how it reacts.

Dale

The biggest problem with stock and similar replacement shocks like Konis and Bilsteins is the stock, hard rubber bump stop in the rear. If you were to check the amount of shock travel available between the top of the shock and the bottom of the stock, hard, rubber bump stop, you would be surprised. The reason the stock springs positioned the rear of the car so high was very likely to have enough shock travel.

With my konis and Tein H Tech springs, I think I had 1/2" of shock travel.

The lack of shock travel causes the shock to bottom out against the very hard rubber bump stops resulting in a harsh, unpleasant experience.

I think you can remedy the situation by removing the stock bump stops and replacing them with an after market micro-cellular polyurethane bump stop like Fat Cat did with the Miata bump stops. The OE Miata used the same type of bump stops that the FD did.
https://www.fatcatmotorsports.com/FCM_bump_stops.htm

Here's a pic of the stock upper shock mount with the bump stop in place
by https://www.flickr.com/photos/26005589@N06/, on Flickr

Pic of bump stop removed
by https://www.flickr.com/photos/26005589@N06/, on Flickr

Here's another example from my Spec Miata of too low of a ride height and the Fat Cat MCU bump stop. I added 1/4" of ride height to fix this.
by https://www.flickr.com/photos/26005589@N06/, on Flickr

that is extremely unlikely. i've worked for and with Mazda since 1997, and i've seen 1 part that was misbagged in Japan (and heard of one more), it just doesn't happen, there is no slapping. the US warehouses used to do it all the time though,

if you look at a part there is a blue Mazda label, which comes from Japan, and then there is a pick sticker from the warehouse.

oh and there is a picture on the current pick stickers, and this should be looked at because there are some funny ones

One label, long & narrow, typed with the part number, black type on white background. No warehouse pick sticker. As I wrote above, front shocks came from Huntington Beach Mazda, rear shocks from Ray Crowe at Malloy Mazda, bought at different times.

the important number is on this sticker, which used to be blue, but is turning black for current parts.
https://cimg7.ibsrv.net/gimg/www.rx7...e445ca450f.png

My shock absorbers (both types, and from different sources) carry the labels I described pasted on the parts. They were not received in plastic packages with labels as shown in your post. Not sure the labels are still there, but I guess I could check. I am familiar with the type of labels you posted, but not for the shocks. They were packed in boxes.

Do your shocks have the part numbers printed directly on them, like these rear shocks on my '94?


https://cimg8.ibsrv.net/gimg/www.rx7...579700da05.jpg


https://cimg1.ibsrv.net/gimg/www.rx7...9d6e588f05.jpg

"Do your shocks have the part numbers printed directly on them, like these rear shocks on my '94?"

Without removing a wheel, I can just make out a white label with black print on a front shock with "FD1..." on it. It's a paper or plastic label glued to the shock, not painted.

the date is also on there. if we put our white gloves on it should match or predate the cars build date by a little bit.

You are thinking of the OEM 1994 shocks. I am writing of the replacements I installed (see original post). I no longer have the originals. My question is whether these replacements, ordered from Mazda and from Ray Crowe, are truly the "Normal" and not the "Hard" shocks. By the labels, they are the "Normal" variety, but not by my derriere.

Although it isn't clearly shown in my pictures above, my rear shocks have both a label AND a printed-on part number. The left rear is original to the car, while the right rear shock (oddly, the older one) is a dealer replacement for one that leaked. I thought your shocks might have both a label and a printed-on part number, like mine. If those didn't match, it would support your suspicion that they were mislabeled as normal.