I've owned my FD for about a year now. I began modifying it with an aftermarket exhaust install. Every time I replaced one component I would notice another wore down and also needing replacement. I believe the only way to make it right is a block tear down and overhaul.

The engine bay, along with many other components, has a good amount of corrosion. For example, the bracket which supports the radiator has visible corrosion and all the bolts are frozen. More often than not when removing hardware from the engine bay the hardware is damaged, bolt or stud heads snapping off etc. And yes, I've tried to be as delicate as possible using every bolt releasing agent available (PBlaster, BoltFreeze etc.).

What options are available for replacement bolts?

I know there is always Mazda, but aftermarket could save me a fortune. There are numerous bolt and nut companies out there but I don't know how to get bolt size/specifications from the maintenance manuals, and I don't see any marking on individual bolts.

Thus, I turn to the club. What options are available for replacement hardware?

 

I know the exhaust/turbo bolts, OEM is nearly unbeatable. It's made of inconel versus stainless steel in which most aftermarket uses. Inconel being much more heat and stretch resistant. They are very expensive hardware. I get mine from Ray Crowe at Malloy Mazda, a quick search will get you his number.
I'd say replace them all with OEM, it's proven quality. Corrosion and frozen bolts are fairly common on a 10-20 year old car. Consider torching your bolts out btw. If you aren't convinced with OEM I'd recommend ARP, they may not have a vehicle specific application but I'm sure there is hardware with the same specs as ours for another vehicle that could be used. I was considering them for my exhaust mani. studs as I've used them with success in the past.

 

If there are any "U-Pull-it" type salvage yards in your area, try those. For the price of admission ($2 in my area) you can pretty much fill your pockets. The FD is mostly 10mm and 12mm bolts. Look in any 90's era MAZDA or 2nd Gen. Probe. I like the interior areas, especially for plated bolts of various lengths, nuts and even screws and the interior plastic retaining clips. Since those in the interior aren't exposed to elements they're usually in like-new condition.
FWIW, the screw covers on the plastic cowl and hood rod retainers on the 2nd Gen. Probes are also identical to the FD. Some electrical connectors are the same as well.

 

+1 on the junkyard. OE bolts are far and away the best quality.

Next up is McMaster-Carr, they have TONS of hardware for a reasonable price.

For small clips and some bolts, also check out clipsandfasteners.com - I've ordered tons of stuff from them, they have a dizzying array of hardware for a very good price. Some is exact OEM replacement hardware too.

Dale

 

Thanks for the help, I will be doing the overhaul in Knoxville, TN in December. Is there a master list of reputable rotary junkyards?

As for McMaster, is there any way to determining sizing and material of bolts other than physicall measurement. What I was hoping for was a master parts list for car that can be used to identify the bolts.

 

Metric bolts and nuts are....metric bolts and nuts. With VERY few exceptions like engine tension bolts, they don't have to come from a rotary. MAZDA didn't use anything special to assemble the FD, so any MAZDA in the salvage yard will yield what you need...short, long, extra long, with integrated washer...or no washer etc.
10mm, 12 mm and a few 14 mm will just about cover everything under the hood. I think your making it harder than it has to be.

 

I dont think there is any "master" list of any sort.

My local hardware has a wall with different bosses, all female threaded internally. You take your corroded bolt along, screw it into one of the bosses that fits, see what thread size that is marked as, and then go choose your new packet of bolts from the many packets hanging on the wall, various lengths and materials all clearly marked. Its a breeze.

Do you have that kind of thing in the USA?

If not, just go to the scrapyard as suggested. Pick similar year Mazdas or Japanese cars to scrounge over. Take more than you need and just make a bucket or bin in the garage and keep filling it with good bolts you collect. Soon you'll have a nice stash of good bolts whenever you want some

 

You can also get bolt sizing tools, Harbor Freight sells cheapies that do the trick just fine.

A set of digital calipers make it easy for measuring bolt length.

Dale

 

Right, the hardware stores will always have something, but the oem nuts and bolts have the integrated washer design that works much better. I work in aviation where all hardware comes with some part number which makes replacement easier. I don't think all metric bolts are all the same.

 

When buying from the hardware store, should heat tempered bolts and nuts be used anywhere other than exhaust?

 

Malloy for all the odd stuff like exhaust studs and nuts, junkyard for anything else.

 

Yeah, its not worth over complicating it. Aircraft use catalogued bolts for a good reason. Passenger cars, no.

Body bolts- buy new plated stuff (I can get the metric flanged head type you are talking about very easy anywhere, but this is Australia. We're predominately metric here) If you cant buy the flanged ones from hardware stores, just get them from old wrecked Japanese cars.

Engine bolts- specialized things like turbocharger hardware, manifold bolts, etc get from Mazda- Ray at Malloy Mazda and then you dont have to worry if they're right or not.

*I believe Ray's bedroom ceiling has a giant exploded diagram of an RX7 painted on it much like the Sistine Chapel fresco- he memorizes the entire car as he falls asleep each night. Legend has it that when Ray snores, it sounds like "N3A1.......Zzzzzz....N3A2......Zzzzzzzzz..... . That hose will not work in that application......Zzzzzzzzzz.... Use 14-710D-N3A2.......Zzzzzzzzzzz "

 

I buy new stainless bolts from McMaster Carr.
I'd have to look again but I think most of them are 10mm 1.25 thread pitch. You can get a box of 100 for a few bucks. They have an app you can down load for the catalog also.