Garth S

Did the loctite 290 trick on my ex '88 S4 on Aug, 2003: no movement detected at 20,000Km later when I sold it on July, '06.
I have the car back for service at least once yearly - last measured on Aug '08 .... ZERO movement! ( end float is still minimal as well)

5 years, and all is well.

marton

ROG100

Its only guys with small dicks that have to compensate with a large wooden spoon 8>)

The RogerBox is the only way to go - far superior in every way. You Know IT Makes Sense.

Glad the Loctite Fix is working - we miss you Shocki and the family.
Let us know how the R&P replacement works out.

Hilton

It goes in the rodgerbox, no?

Tails

Over 2 or more year ago I decided to go down the loctite 290 route after following GarthS thread on the flexplate clamp. No movement and thrust bearing end play remains the same over the last 9 years.

Prior to loctite, I had continuoud migration of around 3mm after each release and reclamp.

Bottle of loctite around $7.00. Good value for money.

Tails 1990 928S4 Auto

SharkSkin

Still waiting to hear from the first guy that has to change an RMS, torque tube, etc. after loctiting their splines.

My guess is it won't be pretty, and if anyone has had to remove a glued spline they may not be especially excited about sharing their experience.

Z

I've taken one apart after having used the Loctite on it. It didn't exactly fall apart by itself, but then there wasn't any need for high explosives to get it apart either. Heating it up got it loose. I've also read where acetone will help release parts that have been put together with Loctite, but have never tried that. I might try the acetone if I ever have to go back in there. I'm thinking that probably won't be for another 100,000+ miles or so.

Tails

Dave,
I have used loctite in many applications in my career and in this instance with 290, I obtained the Technical Data Sheet and the Material Safety Data Sheet. It is interesting to note that the product has been tested to Mil-S-46163A and ASTM D5363.

The Data Sheet gives the breakloose torque, ISO 10964, pre-torqued to 5N-m is 30 N-m (45lb-in) and (270lb in).

For disassembly:
1. Remove with standard hand tools.
2. In rare instances where hand tools do not work, because of excessive engagement length, apply localized heat to nut and bolt ot approximately 250 degrees C. Dissembly whilst hot.

Your will note that they quote Mil spec, ASTM spec and the ISO standards. Manufacture do not quote these specifications and standards without acceptance and audit procedures within industry.

Tails 1990 928S4 Auto

Black Sea RD

One question is, can this loctited assembly be loosened, repositioned and reclamped in a new postion if needed with the torque tube (TT) and transmission still together in the car. From my experience, no.

The heating and subsequent pulling, prying, tugging and hammering is done upon disassembly of the TT from the car since there is no other way to generate enough force on the assembly to release the drive shaft from the clamp.

These actions usually cause the drive shaft to move within the TT. The heating, tugging and banging actions are also transferred to the engine internals, flywheel seal, TT bearings and if the transmission is still connected, the transmission converter bearings and internals.

The heat needed in this instance will not come from a heat gun, but usually an open flame source, not too good under the car to begin with, from possibly a welding torch or maybe butane cannister. Since the surrounding materials are metal, it will take a long time to heat soak the clamp. The way some are making it sound, it's as if you can run a candle underneath the clamp and give a tug with one hand and the clamp disengages easily. Not.

One thing that is concerning is the white washing of the distinct negative ramifications from using loctite for this purpose. Even from those that are regarded as gurus on this list.

But hey, Loctite sure is cheap!

If cost is an issue, recommend the circlip, bearing and washers routine over loctite.

Constantine

SharkSkin

Tails, I don't have the time to dig up those MIL & ASTM specs but I'm going to guess they are referring to the intended application, threaded fasteners. I'm really not interested in the paper, but real-world experiences on what it took to service the spline after gluing it. Z, care to elaborate? How much heat? How much force to move the spline? Approx. of course.

Just thinking out loud here, not looking for an argument.

Tails

Constantine and Dave,

Great comments. It is always good to present both sides of an argument, the pro and cons that allows individuals to make a considered choice of what they wish to do. One thing about RL it is not a dictatorial process.

If I ever need to remove or move the clamp and spline section of the flexplate, well that is another question. The spec for loctite 290 quote heat to 250 degrees C, however the extraction force required to move the actual splines is the nub or the question of which I don't have an answer. The specifications for 290 has a section on "clean up" as follows:

"Cured product can be removed with a combination of soaking in a Loctite solvent and mechanical abrasion such as a wire brush".

Maybe the way to go would be first to soak the clamp section with solvent to soften up the 290 and if heat is required to brake the bond then air blow dry and apply the heat via a LPG torch or oxy-acetylene ensuring all safety and fire procedures are adhered to.

The actual method of applying axial force to the clamp to brake it loose and move it will require a bit of investigation and lateral thinking to ensure that no damage is done to crankshaft and engine internals.

However, if and when this occasions and if I'm still capable of crawling under and working on the car, I sure that I will be able to devise a method of manufacturing a puller/breaker to remove the spline with no depremental affect on the crankshaft and the internal bearings. Hopefully this will not happen as my car has only 97,000 km on the clock and all is working fine with minimum kilometre clocked up each year as most of the time I away in my motorhome.

Constantine bring up a good point relating to moving and re-clamping. Maybe when and if the clamp is moved after using 290 and then reposition on the spline to give no preloading to the crankshaft, any residue of 290 on the splines will increase the coefficient of friction between both splines and may preclude the further use of any 290? Who knows as the bonding surface is microscopic as the adhesion is by wicking?

As expounded in previous post on the subject of migrating flexplate clamps, I firmely believe Constantine has developed the best method of clamping, however, it is like the old saying goes "horses for courses", so it is up to the individual which route is taken taking all external factors into account in the decision making process of the individual.

As an aside, I once superintended repairing a slipped crankshart main journal within the crankweb where the pin, with a diameter was 550mm, slipped 9.5mm within the crank. In the repair no hammering was used, only heat, dry ice and hydraulic jacks were used. This repair was done in situ as the horsepower of the engine was a mere 6,800HP. Upon completion the engine worked satisfactory.

Tails 1990 928S4 Auto

Z

Starting from the beginning, here's basically how things went in regards to the clamping of the front of the drive shaft. When I initially loosened the clamp, it moved back along the splines, as it typically does, indicating that there had been some pressure on the flexplate. I checked the crank end play and found it to be well within the specified tolerances. I thoroughly cleaned the clamp and shaft as well as I could with brake cleaner, and blew everything dry with compressed air. I applied the Loctite all around the shaft where the splines entered the clamp, and also into the three slots of the clamp. I tightened a new pinch bolt with blue Loctite on it into the clamp to the 66 ft/lbs that some have said Porsche suggested, then marked the junction of the clamp and shaft so that any future clamp movement along the shaft could be easily seen. The assembly was left for a day or two before the engine was started, to make sure that the Loctite had fully cured. After that, the clamp position was checked when oil changes were done, and it had never moved from where it was when I had initialy tightened it with the Loctite applied.

A couple of years after having applied the Loctite, I decided to replace some seals in the transmission, get the transmission lines rebuilt, rebuild the torque tube, and replace the torque converter bearings, mostly as preventative maintance, and to give me something to do as a winter project for that year. At that time the clamp still had not moved at all along the splines of the shaft. When taking everything apart, the front clamp bolt was removed and a small propane torch was used to heat things up. I have no real idea how hot it had to get to loosen the Loctite, but I don't see any reason to think it was much different than what Tails said was the information he got from Loctite. A mapp gas or other hotter torch probably would have sped things up compared to the torch that I used. It's kind of hard to remember any kind of exact amount of force that was required back then. It seems that it really wasn't that much after things got fully warmed up though.

Once the shaft was out of the clamp, I used a toothbrush sized wire brush to clean the remains of the Loctite from both the splines of the shaft and the clamp. That didn't take much effort at all, and the clamp easily slid back and forth on the shaft after I had removed the residue, basically the same as it does with any other clean and loosened clamp and shaft. After everything was put back together, I applied Loctite again the same way I had done originally. That was around six years ago now, and I've never had a reason to touch any of it again since. When checking for any signs of movement, there still hasn't been any. If I ever do have to take things apart again, I might try using the acetone method of loosening the Loctite first, to see how that works. If it doesn't, I'll use heat again.

Black Sea RD

Hi Tails,

To further beat this dead horse, I have all the confidence that you and possibly others will take great care when pulling apart the loctited drive shaft and clamp to minimize any damage to other parts of the car. Owners who do their own work usually can take their time to do so. And it still will not be easy.

The question really comes in when someone brings their car in for service at a shop. Time = money to them and futzing around with a loctited drive shaft and clamp is something they have little patience for, no matter how much you try to explain to them to be careful. Not condemning all shops, but I am positive when presented with this to do, some will reach for the torch and their B.F.H. to get the job done.

Thanks again for the kind words about the clamp and as always I appreciate the discussion about this subject.

Happy New Year to you and your family,
Constantine

SharkSkin

Thanks for the details,Z. It sounds like you just put a small ring of glue around the spline. I had been visualizing a coat of loctite over the whole spline, which sounds like trouble to me. Sounds like it worked out well for you.

Tails

Constantine.

Thanks for your reply and the discussion.

May I also wish you and your family a very Happy New Year for 2009.

Tails 1990 928S4 Auto