Diff input seal
- Thread starter VRSteve
- Start date
If you don't have the tool it's much easier. For the professional techs it's obviously easier than having to go and log out the special tool from storage, otherwise they wouldn't just use the rattle gun.GuidoK said:
I have nothing against using the special tool and if you have it then it's absolutely the way to go. The point is that it's not strictly necessary.
Mangozac said:
And how do you thighten the nut?
Of course the thightening force is less than the force needed to get the nut loose but it has to be set exactly to the mark.
Overshooting the mark means disassembling the diff and installing a new crimp bushing.
Chances are that requires more force than you can hold the flange by hand and an impact gun cant be regulated to an angle.
BTW if the parking brake is strong enough, no impact gun or flange tool is needed at all (for the input flang at least)
I dont know any bmw tech that is too lazy to get a special tool from the tool storage. But I guess that depends on the dealership.
Whats also important for this repair is that you tap in the seal to exactly the right depth. The shaft seals have a protruding lip on the axle side that acts like a dust shield. If its tapped in not far enough it will wear away on the diff axle flange, and if it's tapped in too deep it wont seal.
So take a picture or something that exactly shows how deep it seats stock. (BMW have a special tap in tool for this that doesnt allow it to seat deeper)
Short, controlled bursts of the rattle gun. As with loosening it negates the need to hold the shaft while torquing.GuidoK said:
Look around the various forums and you'll see everybody doing this the rattle gun way. Yes, it needs to be done precisely to prevent damage to the diff, but this isn't impossible.
I'd rather stick with the method bmw recommends.
Especially if you can make this tool yourself in a few minutes from 2 strips of steel, 3 m6 bolts and 3 m6 nuts.
Rattle gun and 'controlled' does not go togheter in my book. If you want to reset the pretension on the bearings you need a torque wrench (actually a drag tension wrench) that reads in Ncm (yes thats centimeters, not meters), to give an idea how precise this is (for different bearing manufacturers you even need different settings).
Using a rattle gun is always less precise than using your hands.
That people on forums do this is imho not a set bar. I see people cutting corners on forums all the time.
Especially if you can make this tool yourself in a few minutes from 2 strips of steel, 3 m6 bolts and 3 m6 nuts.
Rattle gun and 'controlled' does not go togheter in my book. If you want to reset the pretension on the bearings you need a torque wrench (actually a drag tension wrench) that reads in Ncm (yes thats centimeters, not meters), to give an idea how precise this is (for different bearing manufacturers you even need different settings).
Using a rattle gun is always less precise than using your hands.
That people on forums do this is imho not a set bar. I see people cutting corners on forums all the time.
I disagree about the bar set by forums: there are enough knowledgeable people around that if there is sufficient issue with a technique then it soon becomes common knowledge not to do it that way.
I'm not arguing that youre wrong: certainly the special tool is the perfect method. But like I said I've been advised by professionals that I trust 100% that the rattle gun method is sufficient. That's good enough for me. We all need to do whatever we're comfortable with
I'm not arguing that youre wrong: certainly the special tool is the perfect method. But like I said I've been advised by professionals that I trust 100% that the rattle gun method is sufficient. That's good enough for me. We all need to do whatever we're comfortable with
Mangozac said:
Unless it takes 50k miles to wear instead of the usual 200k miles.
By then they're long gone, have moved on to another car etc etc, but that still wouldnt make for a good repair.
What you're saying is only true for problems that arise in shorter timespan.
But a carmaker engineers his products and repair methods to last at least the time of the extended warranty period, so about 5 years.
And a carmaker is foremost engineering repairmethods that work repeatedly as lots of people have to complete that repair with certainty.
Thats why bmw doesnt use an impact gun on this repair but spanner that holds the flange and a handheld nut driver.
Almost all alternative methods I see are done because its 1. faster (so out of lazyness) or 2. cheaper.
And so is this one imho.
You seldomly see an alternative repair method because its engineered better. Except for things like the roof motor allocation (the pixelrichter method), where there's a design flaw, or repairs where bmw had not foreseen a repair.
There's no point us both arguing about this. As I said above, we use the technique we feel is appropriate. If you have the special tool then awesome, it's definitely worth using. If not then an impact driver is an alternative option used successfully by many people over many years, including professionals.