wstrohm

The cat converter came off relatively easily, and also the ABS heat shield and pre-cat heat shield, and the O2 sensor. Unfortunately I have only been able to remove 3 of the 4 nuts/studs holding the pre-cat to the turbo outlet. I was able to get about half a turn on the top rear nut (or the stud, don't know which) but it is harder to turn after being started than it was before. That nut seems to have the problem that if I put any torque on my deep 6-point 14 mm socket, the socket is "pushed" right off the hex portion of the nut. It doesn't help that I can't see it, but I did put a mirror in there and the hex portion is OK. I have the bottom end of the precat still in its hanger, but the hanger bolt is loosened and I can rock the precat back & forth... I don't think there's any real stress on the last nut from poor positioning of the precat. At the moment I am soaking that nut & stud in WD-40 overnight. Does anyone have any advice?

---- Bill

jspecracer7

WD-40 like you're doing and a 6 point box end wrench might do the trick.

wstrohm

jspecracer7,

Funny you should mention that. The only way I could remove the other three nuts (2 came off with studs, one without) was with a long 14 mm box wrench, although it is a 12-point. But I can't get that wrench on the top rear nut; no place to put the handle! I guess I'll find out if the WD-40 helped. Thanks for your reply.

---- Bill

JONSKI

Liquid wrench or any rust-dissoling lubricant should help. Just let it soak for a few hours before you get to work. Apply COPIOUS amounts. I had to take the rollers off of a trailer which had been dipped in salt water for years and I couldn't even budge the nuts without the stuff.

wstrohm

Jonski,

Thanks. It is impossible to spray WD-40 onto that nut/stud because of its location, and I think I'm in trouble because I tried to remove it dry, plus the difficulty I wrote about above. What I finally did last night was fold a small piece of paper towel several times, saturate it with WD-40, then I stuffed the wet paper into the recess and wrapped it around the stud, squeezing it all around. Hopefully that will have helped. I'll know in a few hours.

---- Bill

jspecracer7

Have you tried putting the wrench on it, then spray the wrench with WD-40. It'll catch the wrench and trickle down to where the bolt is. Just an idea.

djantlive

Yeah, try a hose or straw so you can get some WD40 in there, it's hard to get the that nut moving. Apply every hr or so.

I don't think you get get wrench in there. I used a socket.

You may need to tighten it a little, then spray, then loosen. Repeat this a few times if needed. Take it easy and don't bust the nut or it'll bust yours!

You should have also loosen a DP studs all simultaneously, not one at a time. This is like removing the tire lugnuts. Never pull one nut at a time, do them simultaneously. As a last resort, you might want to put some of the bolts (like the lower ones since they are easier) back on to see if that helps. This is true when you get the nuts back on as well. Tighten each bolt a little at a time.

Lastly, put some anti seize on the nuts and studs when you tighten the bolts. Kragen sells those little packs for 99 cents.

Rated R1

First off use PB Blaster. That stuff kicks liquid wrench and WD-40's ****. Second you might want to remove your y-pipe. It is a little more work but it will give you a LOT more visiblity and breathing room.

wstrohm

Well, as you might guess, disaster struck. I did finally get some WD-40 on that top rear pre-cat nut, and was able to get about 2 turns CCW on it when it froze to the stud and I turned over the points of the hex, while using my 14 mm 6-point deep socket. Now I can't get any torque on it at all, of course. All 3 of the other studs are out, and the precat flange will back off about 1/4" from the turbo flange before the 4th nut stops it. That nut is not going anywhere. I think the Mazda locknuts tear up stud threads when they are backed off. So I'm stuck. The only thing I could think of was to go under the car, slide a hacksaw blade into the gap on the pre-cat side of the gasket, and try to cut off the stud. So far I've been about 8 hours at that attempt. Like ocean water trying to turn rocks into sand. Wife is NOT happy. It's her car.

---- Bill

Rated R1

OK go buy some damn PB Blaster and let it soak overnight. Turn the CCW until it freezes then turn it about a 1/4 to half a turn CW. Then turn it CCW until it freezes again. It should gradually work itself out. The nut will more than likely pull the stud out with it. You should also plan on replacing all the nuts and studs. Did you take off the Y-pipeto get better access?

paw140

You're right about the Mazda lock nuts tearing up the stud threads on the way out. I don't know if its the heat or what, but 3 of my 4 nuts did that, and the two where the dp bolts to the cat did that. What a pain in the ***! Luckily, I was pulling the turbos anyway, so it didn't cause me too many problems.

JONSKI

That's what I used, but I couldn't think of the name. It's in a spray bottle and the print and design on the bottle is red, yellow, black, white, and straight out of the 50's. Look for it. All I can say is that I can't believe it got those bolts out of the trailer.

-Jon

wstrohm

Gave up trying to saw the stud; it's hardened steel and I had no leverage. I found a sneaky way around the frozen nut problem. Went under the car, removed the rear turbo's intake pipe (just barely possible). Went topside, removed the assembly that adds together the turbos' output air (is that the "Y" pipe someone mentioned above?). That gave me access to the nut. Got out my Dremel MotoTool and first ground, then used the cutoff tool on, the nut. It separated enough to allow turning it off the stud. Yay, pre-cat is out! However, now the stud was really messed up, and ViseGrips wouldn't remove it, so I hacksawed it back to the good threads and used the double-nut removal technique. I installed the new studs and am now ready to put the car back together after I buy a couple of hoses (one rubber hose had turned into hard plastic) and the necessary gaskets.

Of course I haven't installed the Bonez stuff yet. They sent a sticker that says "Bonez Racing." My wife wouldn't go for that, but I'm thinking of making a sticker that says "No User-Replaceable Parts inside" and putting it on the hood. I certainly hope everything goes together easier than it came apart! The rotary is a simple engine, but the peripheral stuff makes the car very complex.

---- Bill

djantlive

Damn, sounds like you are a grease monkey, a strong one!

That's a lot of work. It must have been really scary to bust the stud. Definitely put some anti seize on the stud and bolt when you put on the DP.

Rated R1

Just don't get sticker shock when you go to buy the turbo to downpipe gasket. LOL

jspecracer7

Good man!!!

It's obvious that you've got grease runnin' in them there veins...

...as for the stickers...I put them on my laptop...

wstrohm

Right on about the sticker shock! Precat-to-turbo outlet gasket was $47; three small gaskets, a large O-ring, a rubber elbow and another short rubber bend came to a total of $106 w/tax.

My Bonez downpipe has a second defect (first was weld splatter in the O2 threads, fixed with spark plug thread chaser). This one is fatal. No clearance between pipe and top front flange hole. Someone had ground away some weld fillet, but stopped when they could see the flange hole. No room to put on a nut, let alone wrench clearance for a deep socket. I called Ari at RP, and he gave me the go-ahead to grind it back for clearance; he said he would replace the DP at no cost if I went through the pipe, which I did, practically as soon as the grinding wheel touched the fillet. So Ari is sending a replacement DP first-day air, which means I'll get it before the Mazda parts come in on Thursday! Ari said he will inspect the DP himself... I wish he had looked at the first one.

I would recommend that anyone who wants one of these DPs make a call to Ari and request that it be closely inspected by RP before it is shipped.

---- Bill

JONSKI

I got the rear (secondary) turbo intake off and on again without going under the car. You'll need a long, thin arm and small ratchet for that. I couldn't believe I did it, either.

wstrohm

Ari was as good as his word; I received the replacement DP today. This one has no weld splatter in the O2 sensor fitting threads, and no problem with the top front flange hole clearance... but wait! The bottom rear flange hole is very near the pipe; OK for a bolt, but no way will it take a nut over my newly-installed stud. Well, someone (probably Ari) taped two bolts to the DP, so I'll use one of those. Tried a fit check of the DP and the flange holes slide over the studs with no problem. But wait! When the flange is snug against the turbo, the tail end of the DP doesn't line up with the Mazda bracket hole! Removed the bracket, cut off the welded-on nut, drilled another 1/2" hole in line with the original, and Dremel-ground the two holes into a large slot. Now the fit looks better... but I won't know for sure until I get the new gasket from Mazda (tomorrow morning, I hope).

I was just thinking... Mazda's price for a new precat and cat is more than I paid for my brand-new 1967 Datsun 1600! (No wonder I'm trying really hard to install the Bonez stuff.)

---- Bill

wstrohm

Done, and no damage except to my hands. We've run the car once on the freeway so far, and only a slight increase in exhaust noise was noted. We'll finish burning off the WD-40 tomorrow on a 100-mile trip and hopefully nothing will fall off. Also hopefully, the car will pass smog now. Can anyone use a FREE used (70 K miles) stock pre-cat and/or cat? My garage cannot handle more dust collectors.

---- Bill

Rated R1

Be sure to go back in and retorque those nuts!!

wstrohm

RatedR1,

Thanks for the tip... how many miles should we put on the car before I do that? And I hope you don't mean ALL the nuts... just the exhaust system, yes?

---- Bill