Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.

Diff input seal

"M" Specific discussion
User avatar
mr wilks
Legend
Legend
Posts: 21894
Joined: Wed Jul 04, 2012 10:02 pm
Location: Lancashire

Diff input seal

Post by mr wilks » Tue Dec 26, 2017 8:28 pm

VRSteve wrote: Tue Dec 26, 2017 2:33 pm
mr wilks wrote: Tue Dec 26, 2017 2:23 pm On the ZM i recently sold i had the passenger side diff seal done , boxes off as you will know , iirc it cost me around £150 parts + labour at my BM indy
Any idea how long it took them??
Just altered my original post as it was misleading , i paid around £150 all done , not parts "+" labour , that should have been parts "&" labour :thumbsup:
3 ZMRs
3 E89s
5 Si coupes
5 Si roadsters
997 C4
TTRS
F82 M4
MK7 Golf Gti
current Bmw 6 Gran Turismo

VRSteve
Member
Member
Posts: 565
Joined: Sat Aug 08, 2015 9:36 pm
Location: West Sussex

Diff input seal

Post by VRSteve » Tue Dec 26, 2017 8:30 pm

mr wilks wrote: Tue Dec 26, 2017 8:28 pm
VRSteve wrote: Tue Dec 26, 2017 2:33 pm
mr wilks wrote: Tue Dec 26, 2017 2:23 pm On the ZM i recently sold i had the passenger side diff seal done , boxes off as you will know , iirc it cost me around £150 parts + labour at my BM indy
Any idea how long it took them??
Just altered my original post as it was misleading , i paid around £150 all done , not parts "+" labour , that should have been parts "&" labour :thumbsup:
:thumbsup:

Really thinking I might just do this myself.

I feel a how to coming on!
///M|Silver Grey|Black Leather|BT|Nav|DSP|Heated Seats|PDC|Stubby|Turner Limiters|Turner Rear Top Mounts|Bilstein B12|Powerflex ARB Bushes|Powerflex Lollipops|M-Track|
SOLD

User avatar
srhutch
Moderator
Moderator
Posts: 26959
Joined: Tue Jun 19, 2007 1:22 pm
Location: East Sussex, UK
Contact:

Diff input seal

Post by srhutch » Tue Dec 26, 2017 9:28 pm

GuidoK wrote: Tue Dec 26, 2017 4:22 pm
VRSteve wrote: Tue Dec 26, 2017 4:09 pm
From what I've read, people mark the nut location in respect to the input shaft and return the nut to that position on re-fitting.
That is the normal procedure when you're just changing out the seal.
This is what I have read also. But suggestion on using an impact gun to undo the nut begs the question of how you know how many revolutions have been made.
Image

User avatar
GuidoK
Lifer
Lifer
Posts: 3171
Joined: Tue Aug 17, 2010 1:37 am
Location: all over the place

Diff input seal

Post by GuidoK » Tue Dec 26, 2017 9:45 pm

^thats because you dont use an impact gun. An impact gun is afaik never used on any of the bmw procedures. Except an m52/m54 vanos overhaul but that isnt a bmw procedure.
An impact gun is a very uncontrollable tool. Its only good for removing rusty fastners because it's shocks loosen the rust.

To loosen the nut you need a special tool to hold the flange. You can buy this tool on ebay for about €50.
I have one too. this is the tool:
I dont know exactly how you call this in english (I can think of multiple names)
Image

This is a must have tool if you do a lot of transmission work on both cars and (old) motorbikes.
You can also easily make this tool yourself.
Z4 3.0i | ESS TS2+ | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | fully polybushed | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers | Sachs Race Engineering clutch

Mangozac
Senior Member
Senior Member
Posts: 1103
Joined: Sat Aug 08, 2009 5:33 am
Location: QLD, Australia
Contact:

Diff input seal

Post by Mangozac » Tue Dec 26, 2017 11:57 pm

We did the seals on an E36 M3 earlier in the year, with advice from some BMW technician mates. They are very skilled techs and I trust their advice without hesitation.

They mark the point and use a rattle gun, so we did the same. You can mark it in such a way as to tell how many turns is correct. This is much easier than dicking around with special tools.

By the way, OP: if you're going to do one seal you might as well do all three while the diff is off.
Current: 06 E85 M Silbergrau
Previous: E85 3.0si Silbergrau, 03 E85 2.5i Maldives Blue.
Mods: Gaptech OTH+R, Dension Gateway 300 with USB, CDV-, clear side indicators, euro tails, stubby, MFSW retrofit, OEM Bluetooth/VR

User avatar
GuidoK
Lifer
Lifer
Posts: 3171
Joined: Tue Aug 17, 2010 1:37 am
Location: all over the place

Diff input seal

Post by GuidoK » Wed Dec 27, 2017 7:41 am

Mangozac wrote: Tue Dec 26, 2017 11:57 pm This is much easier than dicking around with special tools.
How do you know it's easier?
Have you tried the tool?
Or are you speculating?
Z4 3.0i | ESS TS2+ | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | fully polybushed | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers | Sachs Race Engineering clutch

Mangozac
Senior Member
Senior Member
Posts: 1103
Joined: Sat Aug 08, 2009 5:33 am
Location: QLD, Australia
Contact:

Diff input seal

Post by Mangozac » Thu Dec 28, 2017 2:06 am

GuidoK wrote: Wed Dec 27, 2017 7:41 am
Mangozac wrote: Tue Dec 26, 2017 11:57 pm This is much easier than dicking around with special tools.
How do you know it's easier?
Have you tried the tool?
Or are you speculating?
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.

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.
Current: 06 E85 M Silbergrau
Previous: E85 3.0si Silbergrau, 03 E85 2.5i Maldives Blue.
Mods: Gaptech OTH+R, Dension Gateway 300 with USB, CDV-, clear side indicators, euro tails, stubby, MFSW retrofit, OEM Bluetooth/VR

User avatar
GuidoK
Lifer
Lifer
Posts: 3171
Joined: Tue Aug 17, 2010 1:37 am
Location: all over the place

Diff input seal

Post by GuidoK » Thu Dec 28, 2017 10:45 am

Mangozac wrote: Thu Dec 28, 2017 2:06 am The point is that it's not strictly necessary.
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) :D

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)
Z4 3.0i | ESS TS2+ | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | fully polybushed | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers | Sachs Race Engineering clutch

VRSteve
Member
Member
Posts: 565
Joined: Sat Aug 08, 2015 9:36 pm
Location: West Sussex

Diff input seal

Post by VRSteve » Thu Dec 28, 2017 11:37 am

I have to admit,

The possibility of screwing this up has put me off and its booked into Walkers (My local indy) to be done after new year.
Its also having the MOT done at the same time!
///M|Silver Grey|Black Leather|BT|Nav|DSP|Heated Seats|PDC|Stubby|Turner Limiters|Turner Rear Top Mounts|Bilstein B12|Powerflex ARB Bushes|Powerflex Lollipops|M-Track|
SOLD

Mangozac
Senior Member
Senior Member
Posts: 1103
Joined: Sat Aug 08, 2009 5:33 am
Location: QLD, Australia
Contact:

Diff input seal

Post by Mangozac » Thu Dec 28, 2017 11:59 am

GuidoK wrote: Thu Dec 28, 2017 10:45 am And how do you thighten the nut?
Short, controlled bursts of the rattle gun. As with loosening it negates the need to hold the shaft while torquing.

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.
Current: 06 E85 M Silbergrau
Previous: E85 3.0si Silbergrau, 03 E85 2.5i Maldives Blue.
Mods: Gaptech OTH+R, Dension Gateway 300 with USB, CDV-, clear side indicators, euro tails, stubby, MFSW retrofit, OEM Bluetooth/VR

User avatar
GuidoK
Lifer
Lifer
Posts: 3171
Joined: Tue Aug 17, 2010 1:37 am
Location: all over the place

Diff input seal

Post by GuidoK » Thu Dec 28, 2017 12:21 pm

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.
Z4 3.0i | ESS TS2+ | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | fully polybushed | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers | Sachs Race Engineering clutch

Mangozac
Senior Member
Senior Member
Posts: 1103
Joined: Sat Aug 08, 2009 5:33 am
Location: QLD, Australia
Contact:

Diff input seal

Post by Mangozac » Fri Dec 29, 2017 12:25 am

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 :thumbsup:
Current: 06 E85 M Silbergrau
Previous: E85 3.0si Silbergrau, 03 E85 2.5i Maldives Blue.
Mods: Gaptech OTH+R, Dension Gateway 300 with USB, CDV-, clear side indicators, euro tails, stubby, MFSW retrofit, OEM Bluetooth/VR

User avatar
GuidoK
Lifer
Lifer
Posts: 3171
Joined: Tue Aug 17, 2010 1:37 am
Location: all over the place

Diff input seal

Post by GuidoK » Fri Dec 29, 2017 10:34 am

Mangozac wrote: Fri Dec 29, 2017 12:25 am 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.
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.
Z4 3.0i | ESS TS2+ | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | fully polybushed | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers | Sachs Race Engineering clutch

Mangozac
Senior Member
Senior Member
Posts: 1103
Joined: Sat Aug 08, 2009 5:33 am
Location: QLD, Australia
Contact:

Diff input seal

Post by Mangozac » Sat Dec 30, 2017 4:33 am

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.
Current: 06 E85 M Silbergrau
Previous: E85 3.0si Silbergrau, 03 E85 2.5i Maldives Blue.
Mods: Gaptech OTH+R, Dension Gateway 300 with USB, CDV-, clear side indicators, euro tails, stubby, MFSW retrofit, OEM Bluetooth/VR

Post Reply