Has anyone substituted a stronger bolt? I'm thinking stainless steel with a lock washer or wave washer.

 

Using a stud that remains in the housing with lock nuts would be the best setup.

 

I guess you know better than Henkel corp which claims the 271 is the strongest highest tensile locker. Most of the automated dispensed lockers of the solid type are heat cured. I wonder if the products Andybump has mentioned are relatively new. There are many companies that produce these dry products, which most are non-reactive.

 

This was already determined.

 

How would you twist the cap to get it off?

 

I personally like the idea of just re-drilling and tapping to a M6X1mm thread. It looks like there is plenty of material to accommodate the larger size.

There are many grades of stainless steel, and most are not as strong as the light alloy materials used in SAE fasteners. These could be made from 17-4, 440 or 410 which would be capable and not require a coating for corrosion protection.

If someone would like to try a stud setup I could make them. I would use 17-4 thread rolled with a high quality nylox nut. The only issue is that the 17-4 will not thread lock well and might back out when loosening. I could increase the radial dims on the side that screws into the housing to improve the fit. I don't think a true interference fit would be a good idea.

 

https://www.mcmaster.com/products/th...-head-screws~/
Self locking similar to thread locker (lock washers don't work very good - probably why GM used thread locker). But you may strip the aluminum threads instead of shearing off the bolt head.

But you shouldn't have a problem with the OEM screws if the instructions in the service manual are followed.

 

And I guess you have inside information that the C8 DCT filter bolts use Henkel 271? Didn't think so.

 

No I don't, never implied that and don't believe that is the case. Engineers at Henkel have informed me in the past that it's their highest strength product. Just a statement about the locking capabilities of the liquid vs the solid.

 

The facts are that not all dry thread lockers are "interference fit", and we do not know the brand, or the type within that brand, of thread locker that is on the bolts supplied in the kit. We we do not know it relative strength and cannot tell from its color, because we do not know what it is. And, none of that matters anyway for the issue at hand. Regardless of what type it is, or what color it is, or what strength it has, there will be residue in the thread holes that need to be cleaned before new bolts are inserted. We also know that there is no 5 mm thread chaser, so that means another method for cleaning the threads must be used. Most competent techs and most experienced DIYeres can figure out a way to do that - several have been suggested. We also know that the bolts can be twisted off - but we do not know if that was from failure to clean the threads, or just from careless over torquing, or a combination. When inserting the new bolts, with the pre-applied thread locker, there will be a natural resistance due to the new thread locker. This means that if the threads are not cleaned, an issue with residual thread locker might not be recognized because some resistance is expected. Bottom line - clean the threads and properly torque the new bolts.

 

anyone know the written procedure GM has given the their Dealer? they tell me it is different from the service manual ( using a thread chaser- that nobody makes)
But are Not willing to share it- sounds like if dealer breaks a bolt they just button it up and cover it with the shear panel - then you have to figure it out $$$$
this like my C6 when the roof delaminated and came apart - how about wait for a part - no loan car? hey I’m 74- had corvettes since my 20’s…… but when they screw up? they screw up! they sold a bunch of these now- 05 thru 07 C6 roofs failed- Sound familiar- we are not being unreasonable expecting BETTER than this
thanks Dave

 

I can appreciate all this talk about the fasteners, cleaning the threads and such, but I have changed my DCT filter at least six times now without a problem and I have not cleaned the filter housing threads. Using a 1/4" mini ratchet set, I have been able to run the bolts all the way in by hand with very minimal resistance until seated and then torqued first to 30 lb-in and then 53 lb-in in a criss-cross pattern and have never had a problem. I have not had a problem removing the bolts either. I would run a thread chaser in the housing if there was one available. I go by feel - I'll know if something is not assembling right and if it isn't, I'll stop, investigate and remedy what's wrong. If I had to clean the housing threads, I would first clean a used bolt and using a solvent, run it through the threads until it felt good and passed visual inspection.

 

There is no revision to the service manual for this that I'm aware of. Written clarifications to the service procedures come in the form of service bulletins and I haven't seen one that clarifies the fastener installation procedure. If the dealer won't show you a copy then I'd assume it is BS.

 

Finally.... No dealer is doing this chase thing except at the bar! Thanks

 

Andy, can guess it's not a known (read to expensive) brand, probably some cheap copy made in China!

Recall my 2017 Grand Sport 1st engine oil change issue. Did it myself as did not trust large Chevy Dealer in town I had used to do it right.

Had done my prior 2014 C7 Z51 dry sump so brought tools needed when I crawled under the car. BUT turned out Grand Sport had a longer liquid/liquid engine oil cooler and could not get side drain plug out with an extension and 1/2 inch drive ratchet i brought. Tried the 12 point box wrench BUT it was rounding the relatively soft, cheap drain plug hex. Also had a flare nut wrench that fit. Same rounding and it would not budge! Had to resort to my 6 point socket BUT could not get even pry bar in the socket end. No room with the longer engine cooling heat exchanger.

Had to use and old BUT good pipe wrench on the sides of the socket. Had to use a pipe on the handle to get enough leverage to have it start! Recall my plan was to get a hard to find 6 point box wrench if the wrench slipped on the socket sides.! Fortunately the pipe wrench on 6 point socket WITH pipe on handle worked.

Turned out it looked like a funny brown Loc-Tite on the plug. BTW the from pan plug had nothing! Whatever was on the plug was not a "Known Brand!" Probably whatever from a low cost supplier!


Note after it wasn't need bough a 6 point box wrench! Can get from Snap-On for ~$35. Found on Amazon for ~$19. Made in Mexico! Not in pick but 1st tried a 12 point box wrench but it was starting to round the cheap GM drain plug hex!

 

District MGR and dealer told me that Gm has furnished guidance for filter change that does not require the use of the non existent Thread Chaser- I printed out
Madd Matts guidance to remove the bolts- leave cartridge in place - clean bolt on wire wheel- run it as a chaser thru bolt holes- then remove cartridge housing-
showed this to dealer
I asked Other local dealer not to change filter (1200 miles)at year one of my 22- they insisted it had to be done Now- just had fluid changed at 3750 miles at 3 year interval -

I don’t think they wanted to touch the filter- they said change it at 7500 miles thanks

 

Yup. In addition to 12 point sockets, I have 6 point sockets in metric and SAE from small to very large, pipe wrenches from small to very very large, and some vintage wrenches I find useful from time to time. I also have 6 and 12 point combination wrenches in SAE and metric. I got most of it a good while ago so most all is USA made. I find it all useful at various times. I also have torque wrenches with various ranges, some click, and some dial type. I have real nice dial type for low torque applications. One thing I do not have, and never had, is a set of chasers. When necessary I just clean threads with a wire brush on a tool - drill or dremel - or by hand - whatever access limits requires.

From what I read about chasers, they are intentionally not made of hardened steel - so they will ostensibly not cut new threads. They are for repairing damaged threads and just for cleaning threads. In this case at hand, we are not "repairing" thread, only cleaning them - if necessary - and that does not require a chaser.

 

ask for the heads of the bolt heads that were snapped off. If they produce one, they are responsible. A bolt head that was snapped off would have fallen off in the street while driving. If they present one, they caused the damage.
also ask to see the thread chaser tool they use to clean the threads? If they cant produce it then they did not follow gms procedure and caused it.

 

No dealer is going to be able to produce a 5 mm thread chaser. It does not appear that one exists. There are other ways to clean those threads or to insure that those threads are clean. An experienced tech will know that. An inexperienced tech may not, but then, you can probably damage threads with a thread chaser if you do not know what you are doing. If the tech does produce something, will you know if its chaser or a tap? They do, or can, look different, but not always. The main difference is that the chaser is supposed to clean threads and "restore" threads, but not cut new threads. So, its not typically made of hardened steel. Taps cut threads and are made of hardened steel. In this case we are neither restoring theads nor cutting theads, so we do not really need a chaser - just a way to clean or insure that threads are clean. Below are some images of threads and taps. You can see they can look different, or similar. One of them is actually a 5 mm "frame tap" that claims it can be used as a chaser. Is that ok?

 

Make one end of the threaded stud long enough to extend through the housing with enough threads exposed so you could run a locking nut down on it. This would be a permanent installation and the housing threads would never be disturbed again.