2002 Arizona Rebuild

[Lumphammer]

Not had much time but got the engine out. Pretty misterable experience, everything was siezed or required the force of Zeus to undo. The exhaust manifold and cat was particularly bad, had to undo the cat from the mid section, the bell housing bolts that hold the cat bracket and the manifold to head bolts so the cat and manifold could be drawn up in the engine bay to get to the three bolts that hold the manifold to the cat. Everything is rust

Some pictures - stripped stuff off the engine

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Then after a lot of misery underneath the car lifted the engine out

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Put the engine on the stand. It's a cheap eBay stand, I made some custom bolts to account for the fine threads on the block when i did the Mk1 but i think that G19 engineering sell a set that does the same now

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Engine bay without the engine. After the picture i had a go at the subframe with a chisel and it went through in a couple of places so will be getting a second hand better condition one. All the subframes and suspension will be getting blasted, zinc metal sprayed and epoxy so there's no point starting with a bad one

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This is a set of OEM mazda panels for the front chassis rails. You can still buy them remarkably. I think they were in the region of £300 all together which isn't bad for OEM panels in my opinion, if anyone want's the Mazda parts numbers I'll dig them out. Shows the two layers for the crumple zone.

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I'm hoping to get a front leg section off a breaker to practise how i want to do the repair, I'm going to do it as close to original as possible. I'm not really sure this is the best way to do it, it's certainly not the easiest, but i just want to.. and it's my car so..

[Mazda Mender]

I hope that you are also attacking the subframe etc ,power steering pipes ect ,while it's a case of it all out /off and while I have gone this far I may as well bud...
M-m

[Lumphammer]

The subframe is too far gone, it's got holes, but I'll be getting a good second hand one. All the subframes and suspension will be getting blasted and then zinc metal sprayed, then epoxy. The cars going on the rotisserie once the front chassis rails are done, don't worry everything is going to be done. I'll replace the ps lines, they've got pitting rust on them so imo they're past saving

[Mazda Mender]

The subframe is too far gone, it's got holes, but I'll be getting a good second hand one. All the subframes and suspension will be getting blasted and then zinc metal sprayed, then epoxy. The cars going on the rotisserie once the front chassis rails are done, don't worry everything is going to be done. I'll replace the ps lines, they've got pitting rust on them so imo they're past saving

M-m

[Lumphammer]

Had a few couple hour stints. This is the state of one of the chassis rail sections before I started doing anything. On the outside it's not that bad compared to a lot although the top part is quite bad on this nearside

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Took out the subframe and all suspension to get more space. Lots of rusty nuts, subframe is junk with pitting and holes etc.

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To get access I removed the headlight frame and the top rail at the front where the latch mounts to

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After drilling out rusty spot welds and taking a rusted part of the front arm part the replacement top piece sitting where it needs to go eventually. Did the cut on the flat sections so it'll be easier to make the replacement and dress etc

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This is why i'm doing it in a complicated way, the spalling rust goes all the way under the front subframe mount assembly inside the chassis rail, beneath the shock tower.

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I don't like the way others do front chassis rail repair, they cut it just before this point and weld in a thick single layer piece, the thing i loath is that they're leaving a load of spalling rust filled metal inside the subframe mount assembly structure. I think this is sketchy AF so i'm not doing that.

After today's rusty adventure I think i'm going to remove the 4mm plate beneath the assembly, the one the subframe bolts to and the shock reinforcement piece inside the wheel arch. This should let me remove about 4/5th of the original outer skin and all the inner skin of the chassis rail. With them removed i should be able to clean up any rust left over inside the assembly, treat and begin reassembling. I'm going to have to jig the front of the car (off of.. something..?) because it's all going to get a bit floppy

[Mazda Mender]

M-m

[Lumphammer]

Today didn't go as hoped, the way the front chassis rail is fabricated is awkward and hard to disassemble.

The front subframe mount in the chassis rail is two studs spot welded to a thick inner tube which is then welded to the 4mm mounting plate on the underside and a formed steel plate on the inside, the plate joins the sides of the tube to the chassis rail which is down to single thickness at that point

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Showing strut tower side bracing which runs all the way down to the base of the chassis rail

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The 4mm base plate had to be chopped up to get it off because it's welded to the base of the tube holding the studs

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Several spot welds later the stuf mounting assembly was removed

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Stud mounting assembly. It's still got a bit of the 4mm mounting plate left on it and needs a good cleanup. Going to have more of a look at it becasue i can't work out how mazda do the original layup. I *think* the bottom of the tubes must be welded to the 4mm base plate first and then to top lot inserted from above.. not sure..

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Rot goes further back. After the subframe mounts it has about 4" where it goes back to double skin. I didn't know that but it probably hasn't helped this.. which is pretty bad

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At this point i think i'm committed to rebuilding most of it back to the bulkhead. bugger.

[blackyb]

A challenge for 2023. Take your time and dont rush. You'll get there.

[Lumphammer]

Thanks blacky, hopefully get there eventually

Through looking at it a bit I worked out how the subframe mount was made in the factory. The lower part - the 5mm base plate the subframe bolts to, is one part with the two 23mm cups welded to it. This is welded to the outer leg and later on the studs are pressed in as another unit from above. From witness marks underneath I guessed the studs have a "spline" rolled into them to provide a very strong interference fit into the base plate. The only way to get an interference fit thing like that apart is to relieve it so I tried that.

Mounted the stud unit in the mill and carefully cut down until a split appeared - can see it splitting in the picture

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Then clamped it in the vice and cut a slot to get purchase with the chisel, a couple of hits and it starts moving

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The cup came off pretty well as the interference fit was relieved

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The extracted stud unit. This probably looks now how it would have done in assembly. Bit less rust then!

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The studs themselves are actually one part, which was unexpected. I would guess these are high tensile bolts, probably 10/12.9. I don't have the ability to remake these

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"spline" major diameter, it's an odd size but there's certainly a reason. From measurements on the mating part I'm going to try something IRO 15.3mm female size when i remake the base plate

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Remade the panel that goes between the strut tower arms, I used 1.5mm steel as the original. A pair or 3mm washers for same reason

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As shown I only bothered to do one 4mm raised dimple with an 8mm captive nut behind for the washer bottle. There's two on the original plus a raised mounting lug (I think for the OEM air box..?) but i only used the one so i only made the one - "CBA" etc

I just used a bit of nylon with a recess machined and then an alu punch with a pin for registration. Drilled an 8mm hole and then whack-whack-whack etc

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This is the assembly put together, on the rusty old rail and on the new panel

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I was feeling a bit daunted by this part but I think it's going OK.

I haven't seen anyone do this before so hopefully someone else might get information from the pictures of what it looks like

[blackyb]

Done well, certainly maintaining the Menders ethos.

[Lumphammer]

Don't have so much time at the moment but had today hacking out rust and got the replacement rail test fitted in place

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I machined two new cups and cut a base plate for the replacement subframe mount. I chose a bore of 15.25mm and the height of the cups of 15.50mm. The OD of the cups is 23mm which is the same as the original. I made a brass thingy to register the bore with the 12.5mm bore in the 5mm base plate, the spacing between the two base plate holes is 70mm which is critical.

The bore is a guestimate.. I have access to a 20 ton press, i hope that's enough - I'm trying to recreate a part I can't buy and cant get data on so.. dunno..

01_plate.jpg (409.57 KiB) Viewed 2822 times

Given it's 5mm plate and a critical part i asked a friend to TIG it, he did a cracking job. with the 45 degree chamfer i machined on it there's virtually no protrusion which is important because there's not much clearance on the pressing in the Mazda panel. Mazda electrically weld the cups to the plate, a chamfer and TIG was the closest I could do. I think it's good

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The reason i'm doing this different to literally every other person is I don't like the way everyone else fixes MK2 chassis rail rust. Whilst i'm probably not the worlds most rounded person I like to think i'm not a total nucking futter either. This bit here where the brake line mounts to:

02_rusty_thing.jpg (427.78 KiB) Viewed 2822 times

Is utterly festooned with rust, in the chassis rail behind the subframe mount is almost as gone as the front part that everyone replaces. Your can't see it, it's all on the inside, like the rust under the 5mm base plate, completely invisible

[Lumphammer]

For anyone rebuilding a rusty piece of junk, worth next to nothing, with no spare time, and having to plan for every minute of "garage time"

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[blackyb]

If a jobs worth doing take your time and do it once and do it right.
Never rush as rushing is going to lead to making mistakes.

[Mazda Mender]

For anyone rebuilding a rusty piece of junk, worth next to nothing, with no spare time, and having to plan for every minute of "garage time"

never_give_up.jpg

You love it
M-m

[Lumphammer]

All of this is 1.5mm steel as original. I think all the major structural forms are 1.5mm

The curved section that joins the frame rails, bulkhead and chassis rails had some bad rust under where the chassis rail mounts. Cut out the rust and made some new bits to go in

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Remade the piece that joins the frame rail to the chassis rail, it has the bracket where the hardlines go to the flexi for the brake. It's got a funny curve on the engine bay side

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After a bit of persuasion got the joins nice

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Welding the existing bracket back on. It's pretty thick steel so i used 10mm plug welds to get penetration. Linished it back both sides

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Fitment is OK, the bracket needs a bit of hammering down i think i clamped it slightly squiffy

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Painted the whole lot in some weld through because i had some mixed up. It'll do to keep it from rusting but before it goes on i'll media blast and put some epoxy on the non-mating surfaces instead.

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I'm not going to fit these until after the arms and everything else is welded in because with them off i can get some good clamping between the rail to the lower mounting piece. They need some plug weld holes drilling too, obviously!