Fitting Repair

Have you tried chasing the threads?

http://www.carcraft.com/techarticles/thread_chasing/

nut is steel. When it was removed it took threads with it. Now the nut can be slid on almost fully with low resistance. Do you think using an original size die on the fitting may help?

No, will not work. You would have to have additional material on the outside diameter. (thread major diameter) That is the portion that came off with the nut.

It looks that choice of material was inadequate...(Aluminum versus steel nut-was it stainless?)

But mostly thread repairs were done with Helicoils !!

I,ve have driven European car with Al. headblock ,that the plug thread was repaired with Helicoil - several years !!

Recomended -to do it before any welding that will distort and probably damage too.

To my knowledge, Heli-Coils are only for internal threads. It appears that the threads that are stripped on his fitting are external threads.

Use a radiator hose clamp.

tried - failed, and it took turbo with it due to sudden loss of oil....

Take it to a welding shop. They can cut the existing fitting off and weld a new one in its place, if you can find a new Aluminum fitting.

In an emergency the shop MAY be able to build up the metal and re-thread.

I see a hex shape. Is that part of the core or the nipple? I assume part of the core, allowing a wrench to countertorque the nipple when being threaded in or out.

Can you remove the offending nipple and replace with new?

it is aluminium fitting welded on aluminium rad, - not an option.

From your post, I assume it is an aluminum turbo inter-cooler that you are connecting to from your turbo charger.

You might try an aerospace fitting supplier, ie: Parker Hannifin Corporation, possibly Swageloc or others, to see if they carry a fitting of the correct material, thread and type that will match the thread in the corresponding nut. I believe you stated the damaged threads were on an aluminum connection piece. If you can find a fitting with the corresponding male threads and the correct material, a good (reputable) machine shop/weld shop should be able to cut the damaged section off and weld a suitable new threaded fitting onto/into the damaged piece. (or, a good machine shop can make a new fitting to weld onto/into the existing. Probably cheaper to by a fitting if you can find one on the shelf and have them modify it to fit) Regarding terminology, you might reference it as a "conversion fitting", or if provided the photograph that you included in your post, I'm quite sure that a good fitting supplier will match you up with something that will work. Either way. it's not going to be a "cheap" repair, but since you've already burned up/locked up one turbo, I don't think you'd want to gamble on a second one, as proud as the dealers are of them!!!

My next question is why did the threads gall so bad that they came off with the nut. Is the nut stainless/threads aluminum?? Turbo charger heat?? Once repaired, when reinstalling, you might use some type of anti-seize compound on the new threads to prevent the same from reocccurring in the future. Good luck!!

JB Weld. It works on all metals and I use it a lot on high pressure fittings including hydraulics that often times see 2500+ PSI working pressures.

are you suggesting to build -up material and recut threads. How about shear forces where JB weld will be bonded? Is it not going to pull it off, there will be heat expansion too..

If it was me I would just clean it up good and put the nut back on with a good dose of JB weld under it.
http://jbweld.net/products/jbweld.php

Mechanics -- you can use J-B WELD with confidence. It is designed for safe, reliable, permanent repairs in engine compartments and heated environments up to 500° F. It's strong as steel and impervious to water, gasoline, chemicals, and acids. Working with J-B WELD is quick, easy, and convenient -- and saves you time, work, and money!

Not recommended for use on manifolds, exhaust systems, and other engine components which normally operate at temperatures above 500° F.

I once made the teeth of a worm gear for a telescope drive out of JB Weld. I used a nylon threaded rod to form the gear teeth. JB Weld doesn't stick to the nylon, so when I removed it, the gear was exactly the right shape for a steel threaded rod to drive it.

Maybe use a nylon nut of the right size to form the JB Weld threads, and then when it hardens, replace it with the metal nut.

I used JB Weld to repair a high pressure pump casing that was cracked, that I picked up for pennies on the dollar. Haven't had a lick of trouble with it since.

Your replacement hose probably failed because there is no lip to hold the clamped hose in place....I would have a hose fitting with a lip on it welded to the existing stub...

http://www.carcraft.com/techarticles/ccrp_1112_project_sten_small_block_v8_swap/photo_15.html

This may sound crazy, but I actually did it once and it worked. I can't really tell from the picture what your size proportions are, but if you think you have enough wall thickness on the fitting, you could try pipe-tapping the ID of the offending fitting and screwing in an adaptor.

current dimensions:"

I.D. - 15mm

O.D. - 20.5mm

Tap the inside with a BSP female thread and screw in a fitting with the same thread male?

what BSP size you recommend

waht do you think of BSP female and metric male? M22x1.5?

Change of recommendation: go with #10↑ instead.

3/8" BSP requires a drill of 15.25 but you may still be able to use the existing internal dia if you start with first tap which has got more taper. All the best.

Seeing as there is a hexagon behind the thread it looks as though that part can be unscrewed and replaced.
If so it's probably vastly better than trying the repair.
Del

I agree; If not to allow for disassembly, what is the function of the hex?

G.M., what do the guys at the radiator shop have to say about this?

it is reaction point when tightening flared fitting hose

What? So that you can exert enough torque to strip the threads?
It doesn't make sense!
Del

ha, it is possible if a mechanic willnot know when to stop

Here we had fusion, perhaps, when aluminum threads ahered to steel nut probably with "mechanics" help...

So an aluminum JIC fitting welded to the core? Yikes!

Might very well be time to involve the radiator guys.

I believe the hex is part of the original threaded cast/forged/machined fitting that provided a means of stabilizing the fitting while the nut was tightened onto the threads. I believe the stripped threaded portion is part of a larger assembly which is somehow attached to the other portion . OP might clarify. My guess, (and it's only a guess) is this is a part for an aluminum inter-cooler for a turbo charger. The inter-cooler would serve the purpose of cooling oil that has passed through the turbo-charger.

I am considering the JB-weld option. Thanks to tcmtech and all who responded.

You bet your turbine that it will work?

Well, if JB Weld is as good as tcmtech says, the next disassembly will likely result in the fitting shearing off completely.

now or later the rad is in same condition really.

I am planning to chase thread leftovers, cut a few longtitudional grooves to make better grip against torsion shear forces, apply 1mm layer of JB weld evenly, let it fully cure and rethread. I am expecting to know rightaway if it holds, during rethreading.

By all means, keep us posted....

"now or later the rad is in same condition really."

Well, there is that I suppose. Never know, might get another four years out of it.

I would also be curious to hear how it turns out. Please let us know. Good luck.

I've never yet met an epoxy or suchlike that was anywhere near equivalent to aluminium.
Weld, tap or dismantle...
Del

Try this to repair the fitting:

http://www.muggyweld.com/?view=aluminum

It is a low temperature aluminum brazing alloy that is very high strength and heat tolerant.

You may be able to put a bead around existing fitting, then dress it down and re thread it.Alternatively, you could braze the steel fitting to it using muggy weld alloys.YES ! You can braze steel to aluminum with their Super Alloy #1:With a tensile strength of 20,000 PSI.

Good Luck.

great stuff. if not for this one definitely for future works will be used.

thanks.

I believe the neatest solution would be the "cut an internal thread & screw in an adapter", as suggested earlier. you could even "Loctite" it in place on a "never to be removed" basis.

You know the mechanics Rule of Thumb - "Tighten it till it strips, then back it off half a turn!"

no

he has 15 mm ID and 20 mm OD , so 2.5 mm wall is not enough to tap the inside

i would cut off the damaged part 10 - 15 mm back from the end , place the radiator in a water bath to prevent heat transfer damaging any brazed components , and TIG weld a new half nipple on it

if his engine and turbo is worth the effort then dont stuff around , do it once , do it right

GA mate.

Removing that radiator/oilcooler is work though. If it were me I'd replace the SOB with a new or otherwise serviceable one if I had it off already.

If OP cuts the rooted nipple off flush with the hex that's welded to the tank then an internal thread could be accommodated there and a nipple can then be screwed in. Could do that insitu if the photo is a good indicator of what's around it.

Again - try "Helicoils" to repair the worn thread,very successful !!

You can only repair female threads with an insert system such as Helicoil.

You are right !!

Maybe he can thread one and connect it this way

I would use a good epoxy with a hose clamp. Apply a layer of epoxy first and smooth it out and let it dry, then apply another layer and place the hose over it and use a pair of hose clamps on it. I have had great results with similar repairs using good epoxies (two part) just make sure they are temperature stable.

Devcon manufactures a line of industrial epoxies. Aluminum is one of the variates. These are high quality epoxies that are very good.

If the internal threading is not workable because of the thickness of the protruding tube, there are a few suggestions.

1) Contact a hydraulic repair shop. They are very familiar with these fitting sizes, and should be able to allow you to find a replacement aluminum nut that could then be aluminum welded in place of the existing one. As I look at the picture, I believe that the protruding nipple is welded to the wall of the cooler, then the nut was slid over it and then welded to the wall of the cooler also. This would return the cooler to "as built" condition, allowing all other components to still work.

2) Looking at the picture what I see is a fitting design that the automotive air conditioning repair people refer to as "male internal O ring". Looks to me to be 5/8" size. This is a common replacement hose end for an automotive A/C repair facility. The replacement end of the fitting could be aluminum welded to the tube that is sticking out. The wall thickness of the repair tube is sufficient to thread to internal pipe, or to flare the end, and use a flare conversion adapter on your hose and join.

Is the part metric in its fittings, or not. You need to be sure before before changing anything. Good luck, and let us know.

Greetings G.M.

Sorry if this is a repeat, not enough coffee yet. If I read this correctly this is an oil cooler for a turbo. That would mean very hot oil under a fair amount of pressure. (scratch hose clamp as anything but a temporary fix) I can only say this with the greatest of sympathy, since you have already toasted one turbo. I understand the cooler itself is probably aluminum so the aluminum fitting was not necessarily the wrong material. However, as you have discovered steel pipe fittings and aluminum pipe fittings do not always play well together. So if the unit is worth the expense I say fix it right fix it once. Remove the cooler, take it to a "competant" sevice facility and have the unit rebuilt with steel pipe fittings. If the engine is actually worth it then this option would still be cheaper in the long run than replacing the turbo again and it would also render the assembly servicable in the future.

Oh and just be glad it doesn't have a "plastic" tank!

But I stress again, only if this machine is actually worth the expense.

At some point, there may still be combination of dissimilar metals. The best solution for this that I am aware of is Copper Coat. Similar to Never Seize, but formulated with copper. Fittings will not gall up as yours did.

Perhaps a compression fitting would work?

Hello Folks,

thanks for the thoughts. I will try to find suitable hydraulic fitting with female M22x1.5 which is the hose nut thread. And external or internal BSP/NPT or metric.

The I.D. is actually 14.8mm. O.D. is 20.5mm. the nut I.D. is 20.5mm also and it is M22x1.5 (worn)

I'll try Loctite 28654 too, whether with original nut or maybe better with new hydraulic fitting.

I would find a fitting, probably in stainless that had the male thread on one side and the female thread on the other.

I would clean both the damaged thread and the new female thread with alcohol, then I would screw the new fitting over the damaged threads with a generous helping of JB Weld, and never ever try and take that apart again, ever.....let it cure for a long time, slightly warming will speed up curing....

About the only possible problem is it becomes "too long", watch out for that......or you made need a fitting with a 90° turn to miss something......

Best of luck.

G.M.,

You may even think of potting a sleeve (to strengthen the wall) on the outer by using the epoxies suggested by the Gurus, (Guru in Plural), and then tap 3/8" BSP internally and connect through an adopter to suit the existing nut.

Good luck

Check one of the racing equipment vendors like Summit racing. They have large fuel and oil lines and fittings. Get a fitting and have it welded to the radiator. -- JHF

going for 1/2" BSP femail over old fitting with Loctite, and M22x1.5 male to hose.

most machine shops have a tool called a heli-coil thread repair tool. the theads are cut under sized using a thread die, then a coil spring made of harden steel is screwed around the under sized threads. the spring has the same pitch of your original threads, but are made of hardened metal and are much stronger than the original threads.

Hello, I could not find helicoils for external threads.

You are not going to. That process would require re-cutting the existing fitting to a smaller size, and fitting a coiled strip of SS wire into the new thread. That new thread would then be the same OD as the existing thread was.

That would leave a non sealed fitting, and a starting thread that was very vulnerable to being disrupted when the new female nut was started on to it.

In 45 years of this business, I have never seen the internal thread repair process that Helicoil uses applied to external threads.

Me too.

lyn, if you are refering to the part of bob's comment "... very vulnerable to being disrupted when the new female nut was started on to it.", then, me too, too.

I didn't say that did I?

Nah... I just read between the lines too often!

Got Loctite 28654 yesterday at BRAFASCO .... the grey compound syringe is empty ..they forget to put it in

Package was originally sealed though. Will return it today.

Not meant to be perhaps?

Next time you are going to purchase something as important as that, make sure to purchase it from a reputable organization.... Like Lyn-Door industries.

Take a piece of aluminum round bar, 25mm OD x 35-40 mm long; drill through and tap for your hose fitting; Bore the other end of the bar to fit over the radiator fitting and either weld it on or use JB Weld or some other epoxy. You can make it with any small metal lathe and the correct size tap.