Loctite 518

[Rick Iverson]

Gents:

Paul Rieffle at R-Sport (HIGHLY RECOMMEND for ANY service, ….ANY) has been my go to shop for final assembly preparations. I received this stunning piece today:



I called him about the process to fit the hub into the upright bearing, as I surmised the cold treatment application to the hub was in order. His response was the hub snugly hand pressed into the upright bearing (as pictured).

As this new bearing is quite stiff, Paul recommended a couple drops of Loctite 518 to either the male or female mating surfaces ought to insure the hub would not rotate inside the upright bearing.

Never done this before. Mentorship welcomed.

[sabre1fv]

Loctite characterizes the 518 as a gasket sealant, not an enhancement to 'press-fit' assemblies. One would think that since the assembly didn't require an arbor press that some additional retaining capability would be beneficial especially since the bearing is so stiff. Perhaps Paul misspoke when he provided the Loctite information. Loctite/Henkel does have press-fit grades and wicking grades of its products that would be helpful in this situation. I would double check with Paul on this.

EDIT: Out of curiosity I checked the Loctite/Henkel website and found a series of retaining compounds that could be applicable here; the 648 seems to be the closest match to what you have described (light press fit). There are five different grades of retaining compound, each with different properties to optimize the characteristics of what is needed, so it might be worth reading more about each individual grade before you choose one. The 648 sounds correct to me, but I do not have Paul's experience with this hardware and I would defer to his recommendation after you double-check ;-)

-Jim

[Rick Iverson]

Jim:

Superbly valuable information. Thank you, friend. Happy New to you and yours.

Loctite characterizes the 518 as a gasket sealant, not an enhancement to 'press-fit' assemblies. One would think that since the assembly didn't require an arbor press that some additional retaining capability would be beneficial especially since the bearing is so stiff. Perhaps Paul misspoke when he provided the Loctite information. Loctite/Henkel does have press-fit grades and wicking grades of its products that would be helpful in this situation. I would double check with Paul on this.

EDIT: Out of curiosity I checked the Loctite/Henkel website and found a series of retaining compounds that could be applicable here; the 648 seems to be the closest match to what you have described (light press fit). There are five different grades of retaining compound, each with different properties to optimize the characteristics of what is needed, so it might be worth reading more about each individual grade before you choose one. The 648 sounds correct to me, but I do not have Paul's experience with this hardware and I would defer to his recommendation after you double-check ;-)

-Jim

[GregSmith]

Gents:

Paul Rieffle at R-Sport (HIGHLY RECOMMEND for ANY service, ….ANY) has been my go to shop for final assembly preparations. I received this stunning piece today:



I called him about the process to fit the hub into the upright bearing, as I surmised the cold treatment application to the hub was in order. His response was the hub snugly hand pressed into the upright bearing (as pictured).

As this new bearing is quite stiff, Paul recommended a couple drops of Loctite 518 to either the male or female mating surfaces ought to insure the hub would not rotate inside the upright bearing.

Never done this before. Mentorship welcomed.

Rick,
I would suggest that this would not be necessary, but if you’re worried about it, loctite 290 (green) is a wicking formula for this purpose.

Of greater concern would be the clearance between the faces of the hub and inner cv/tripod flange. They must never touch. Suggest
about .008 before torquing the six bolts. A bit tricky to measure but well worth the effort. This provides for the proper preload on the bearings and, without it, leads to bearing, flange wear and eventual axel failure. Ask me how I know. Maybe this is old news to the group but after fighting loose bolts for some time I finally understood how this assembly is supposed to work…..

Greg Smith

[Rick Iverson]

Greg:

I measured the hub/bearing face difference to be approximately 0.3125”.



I then measured the drive flange depth to be approximately 0.250”.



I am of the opinion your advice is spot on, that the drive flange makes contact with the inner bearing race well before the hub and flange make contact. Torquing the six (6) AN5-45A bolts to the proper specifications (whatever that is) is sufficient to eliminate any movement between the hub and inner race. I GET IT!!

Thx Man, Happy New Year, friend.

Rick,
I would suggest that this would not be necessary, but if you’re worried about it, loctite 290 (green) is a wicking formula for this purpose.

Of greater concern would be the clearance between the faces of the hub and inner cv/tripod flange. They must never touch. Suggest
about .008 before torquing the six bolts. A bit tricky to measure but well worth the effort. This provides for the proper preload on the bearings and, without it, leads to bearing, flange wear and eventual axel failure. Ask me how I know. Maybe this is old news to the group but after fighting loose bolts for some time I finally understood how this assembly is supposed to work…..

Greg Smith

[Rick Iverson]

Greg:

I was thinking about this.

If I understand correctly, 0.0625” is too much gap between the upright bearing inner race and the hub? Then to get the right preload, I need to manufacture a spacer that reduces the gap to 0.008”?

They must never touch. Suggest about .008 before torquing the six bolts. A bit tricky to measure but well worth the effort. This provides for the proper preload on the bearings and, without it, leads to bearing, flange wear and eventual axel failure.

[Fred Michael]

Greg:

I was thinking about this.

If I understand correctly, 0.0625” is too much gap between the upright bearing inner race and the hub? Then to get the right preload, I need to manufacture a spacer that reduces the gap to 0.008”?

No. The gap size is irrelevent as long as there is a gap. The hub is pushing on the inner race of the outer bearing and the cv flange is pushing on the inner race of the inner bearing, that is squeezing the two bearings toward each other and that is giving the preload. If they make contact with each othe then the preload cannot be achieved

[Rick Iverson]

Gents:

I spent a few moments on the phone with RP, and he got my headspace and timing right. I then called Loctite’s race car guy in Jake, and explained the deal to him. He immediately responded with:

• SS 7471 primer;
• and Loctite 609.

These two products are specifically designed for bearing outer race to housing clearance issues. Maximum clearance dimension is 0.005”. He also urged me to use a suitable surface cleaner (e.g. acetone) and a lint free cloth to prepare the surfaces prior to applications. Lastly, do not dilly dally. Once applied, you have ten (10) minutes to final torque specs.

I again checked with Paul, and his estimation on my clearance is one (1) mil. I am not sure I will bother with this process, but if so, VERY sparingly, because the heat to break the bond is 450F.

Thought this might be useful to the archive of general fund of knowledge.