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anyone purchase the proper thread chaser for dct filter bolts?? looks difficult to locate?
wonder is dealers have it - seen post of broken bolts
why would bolts be this soft? also bicycle torque wrench? lots of drama with this car thanks
They provide NEW bolts with LocTite already on the new bolts that are supposed to be used. The purpose is to get the old LocTite out of the threaded casting. I just used a tap on mine when I did it.
Thread chasers will form deformed threads back in place, a tap will remove them. As mentioned the main purpose in this case is likely to clean the threads. A tap can be used but it must be done very carefully to prevent cross threading and removing threads.
I haven't changed my DCT filter myself yet but I plan on using one of the removed screws as a thread chaser. You can cut a groove in the threads lengthwise with a Dremel disk if you want and then clean the threads up with a die and wire brush but I'll probably just clean up the threads with a die and wire brush when do it. I've used fasteners many times to clean up threads by working a bolt/nut in and out.
anyone purchase the proper thread chaser for dct filter bolts?? looks difficult to locate?
wonder is dealers have it - seen post of broken bolts
why would bolts be this soft? also bicycle torque wrench? lots of drama with this car thanks
every single video I’ve watched for the DCT filter, I’ve never seen one mechanic use a thread chaser. I’m not saying It’s a bad idea, but is it really necessary?
every single video I’ve watched for the DCT filter, I’ve never seen one mechanic use a thread chaser. I’m not saying It’s a bad idea, but is it really necessary?
Thread chasing is a step in the official service procedure and people have broken off new bolts when they didn't use a thread chaser. Being necessary depends on the circumstances.
But I agree that most dealers probably don't do it. People may start discovering that they have broken canister bolts or that the bolts break during canister removal on the next DCT filter service.
Problem is aluminum threads are not strong. Inserts should really be used for a part like this since it is almost regularly being removed. It isn't like a once or twice in the vehicle's lifetime. (My current understanding is that inserts haven't been used. But I haven't done this service , just watched some videos of it.)
While I would do the thread chaser, not cutting tap. I would still try to clean the threads out with cleaner, brushes, air, & vacuum first.
Chasers work by pressing the metal into place. It can keep or even make a first time cut thread stronger.
The best threads tapped shouldn't be cut in the first place but pressed similar to the chasing process. (I don't know how these threads were created.)
The most important thing would be proper torque. Dirty/damaged threads lead to improper torque measurement. This is why you go with a nice clean new fastener as well. But it's also important to check those threads. Sometimes they too can be damaged through a number of reasons.
It is super easy to rip aluminum threads, hence you wanting a good torque measurement.
Aluminum bolts into an aluminum housing would be a really bad idea (not saying that is not what GM did, though) because they would gall themselves together the first time they were tightened. Shear strength of a 5mm bolt is not very much and they typically break at the 1st thread where it meets up with the unthreaded shank. That is the location of the highest stress in almost all bolted joint.
Aluminum bolts into an aluminum housing would be a really bad idea...
Porsche learned that lesson on the Macan. They used aluminum bolts on the timing cover. The bolts break and the thing leaks every time. I replaced mine with steel and problem solved. But really, aluminum bolts in an aluminum hole is truly a bad idea.
Has anyone located the thread chaser???- why would Bolts be so soft as to break? looks like wouldn’t take much to break them
Thanks
You can break a bolt without exceeding the installation torque if the threads bind. Most of the applied torque value is to overcome friction and about half of that friction comes from the friction under the head. If the threads bind before the head makes contact then all of the applied torque is going through the threaded portion and the material strength in the threaded area can be exceeded.
Using torque values to obtain the required bolt preload isn't the best way but it is the easiest.
A 22 caliber brass bore cleaning brush at the end of your cordless drill will clean all the old Loctite out of the female threads quite nicely but will do nothing for thread "reforming".
Has anyone located the thread chaser???- why would Bolts be so soft as to break? looks like wouldn’t take much to break them
Thanks
The thread cleaning and chasing is for the female threads in the cast aluminum transmission housing.
Don't know why you would bother chasing threads on a bolt vs. putting a new one in. Unless it's some crazy expensive fastener.
I re-watched some filter change videos. Without taking measuments, it appears like there should be enough material to install an insert if the threads get screwed up.
thread chaser dct filter
