Got a 1985 rt just before Christmas this year and have sent time getting her ready for a trip next month to the south of France (about 2400m round trip). Done all the usual things and have her running pretty sweetly now. Only thing left is the possible overhaul of the water/oil pump. It is not showing any signs of a problem at the tell tail weep but instuctions on here looks straightforward and thought it might be a good idea. Bike has about 70,000miles and appears to have regular oil changes and servicing but dont know if the pump has ever been overhauled. Has anyone experiance and can advise me on whether I'm over worrying.

Hi there, many of us has, and will be glad to help you, but, in my opinion, if there is no dripping at the hole, dont worry, just ride. Once there is a dripping (and it could take another 70k to that) you´ll have plenty of time to fix it, is not a catastrophic failure.
Best regards
JAP

The biggest problem with the oil/water pump is the coolant dissolving the rubber of the mechanical seal. Taking in consideration more the age than the mileage, I would certainly consider replacing the seal before taking a long trip.
It's quite easy to replace it when you are working in the comfort of your workshop but it could be another story when stocked on the side of the road.
As the design has changed over the years, you may have to replace the shaft and the impeller too. The problem is that parts are not cheap.

On another note, if you send me your itinerary and approximate dates, I will try to find some French K guru contacts for you.


Bert

Welcome to the board MGM! I think there are a couple of things to think about on this topic: Your budget with regards to repairs, it can get spendy depending upon what has to be replace, and how far you intend to ride the bike on outings. If its just shorter distances and your weep hole is dry I would tend to agree with JAP and say no worries, but if you plan to do some extended trips you might want to be proactive about the service. As Bert said 25 year old rubber is never in great shape and an attempt at a roadside repair would NOT be fun!

OG

My bad MGM. I was scanning posts to quickly and just saw that your planned trip is 2400m in which case I would definitely at least want to pop the cover and see if it is the original impeller/shaft before heading out on a trip of that length.

OG

Remove the front cover from the water pump and check if the impeller is held on the shaft by a nut or bolt. If it is held by a nut, then it is likely that the seals are the originals. If it is held by a bolt, then the seals and shaft were changed at sometime, as the 1985 bike would have had a nut.
If you find a nut you should change the seals and shaft as the threaded end of the original shaft will shear off when you torque the nut back on to it, which means you will have to remove the broken shaft destroying your new seals in the process. I found all this out the hard way last year.
Check out http://k100rt.aforumfree.com/t1112-waterpump-seal-special-tool on this forum.
Depending on what you find you will probably have to replace the seals, shaft, impeller, and bolt. Everything you need is available from Motorworks and Motobins, and are not too expensive. Complete pumps are also available.

http://www.motorworks.co.uk/bmw/products/product.php?f=i&code=BA_15_40_GA_75&shnew=New&model=K75/100/1100&shnewcode=15&part=Cooling&sub_part=Oil+and+water+pump+parts&modelcode=40&partcode=GA&source_code=BA_15_40_GA_75&header_text=&header_text_image=0

http://www.motobins.co.uk/bmw-parts.php?model=K%20Series

By the way, no coolant/oil dripping from the tell tale hole does not mean that there is not a problem there. The hole through the engine block and pump on my K100RT was completely blocked, and I had to drill the crud and corrosion out of it. I only found out that there was a problem when I found oil in the coolant expansion tank.

I once had a VW Rabbit/Golf that I discovered coolant in the engine sump of. It was not a pretty sight when I tore it down to replace the rod and main bearings. The knocking sound at idle was rather rhythmic though. Coolant eats bearing surfaces quickly.

Thanks all, you have confirmed my suspicions and will play it safe and take a good look this weekend and order the parts needed. Have used both Motobins and Motorworks since starting the project and found both very reliable.

I did wonder how reliable the weep hole would be as an indication of a problem especially given the state of the housing when I first got her. Thanks Avenger GT for the tip on the fragile shaft, had read that the early units were held on my a nut, just the type of feedback that makes this forum such a valuable resource.

MGM,

The weep hole is only an indicator of a big problem (if the seal is leaking). If the rubber starts to disintegrate, nothing will shows up until it's too late.
The best advise when replacing the seal is to use a press or your wise to press the seal into the pump. Avoid using a hammer to pound it in place.

I can attest to the hammer not being the way to go!

Quick note to thank everyone who provided advice allowing me to get the k100 working and reliable for the trip. Rode it from Oxford to the South of France and back with no problems raising money for Charity. Others were braver with bikes ranging from 250 MZ, CanAm and Honda, to a range of larger Jap bikes and a number of K series BM's. The group raised over £20K in total.
The K100 was perfect for the trip, smooth and comfortable averaging 50miles/gal. I had intended to sell her once the trip was complete, but its such a good tool she deserves to be restored to former glory. Thanks again for all the help.

Good for you MGM! Riding and raising money. Doesn't get much better than that!!

OG

Oh, you learned French during your trip ( ).
Hope you found your way back to England and are not writing from a French pub or restaurant!

Cheers

Bert

Looking for some jhelp on where I can fnd the kit to rebuilt water / oil pump on my 85 k100ks.

I have seen all the right up and how too; but don't think I have seen any links or sugestion on where to get the parts.

Click here to open the Motobin page

Select 'Engine parts' on the first pull down menu
select 'Oil pump and Water Pump' on the second pull down menu.

All the parts are listed there.

CF

Parts readily available with the usual suspects.

I bought the LT last week......

Oil and water out of the tell tail.

He said all seals had been replaced and had spent hours trying to fix the problem. 1 week ago.

My thoughts:-

Swap out and at the same time have a good look at the difference  - if any - between the RS and LT pumps in that the way they have been put together (the RS is fine).

I do have a couple of K100s I could swap out the pumps for and leave the K11RS alone if they fit? (My preference)

Rick are you out there mate?

I just want to ride the puppy......

Also, what's the best way to flush the motor to get out the YUCK?

Thanks guys.....

Not sure about swapping pump from one bike to another.

I asked my friend here about that and he said its not a runner.

What is possible is that your previous owner did do the job but damaged the seals in refitting. My friend who did mine is ex BMW and does them blindfold but he was most emphatic about watching it for the first few weeks to make sure all was well. Turned out all was well and it has been to France twice since and been through 2 sets of tyres.

For mine I replaced the shaft and everything on it. Its not worth cutting a few cent and having it go wrong.

Thanks Irish.

Mate Charlie (Gurty) told me the same thing - saying that they probably didn't "lightly" cut back to shaft so the seals are not riding on old crap.....

However the dripping is substantial - there is water in my oil - not to mention my back tyre (I hate that).....

just order the parts from the bins mark

we can do it easy

you will need the water and oil seal ....and a new o ring for the pump body to engine

water in the oil crikey that certainly built up some pressure then

To add something to what Olaf said: while doing a K1100 pump seal I asked the owner to get a secondhand pump housing because the inlet spigot was, well, almost non-existant with corrosion. That was when I found out that there are at least two different types of pump housing. The external dimensions are identical but internally there are some considerable differences in the oilways and the size of the oil pump gears.

charlie99 wrote:just order the parts from the bins mark

we can do it easy

you will need the water and oil seal ....and a new o ring for the pump body to engine

water in the oil crikey that certainly built up some pressure then

Beauty! Mate this time try and finish the old man off - there will be more room in the shed.

Thanks Dai / Olaf

The K1100 will have the small tooth gears but the seal kit is the same. If you can feel an iregularity with your finger nail then ditch the shaft as it will give problems and sooner rather than later.
The earlier large tooth pumps can be used but the gears cannot be swaped. I noted a few weeks ago that the K1200 bricks have the large tooth gears which not only pump more oil but the water pump will spin a bit faster.
Also you can use the old cast type impeller with the new seal if you machine 3mm from the boss on the vane.

Thanks Rick, Charlie said you would put me right..... 
I'm glad NOT to hear things like SH## your going to have to drop the motor out, or, bugger me mate thats a drama...

The pumps can be swapped, K100 to K1100 and vice versa. Just keep the gear sets with their own pumps.

Thanks GT.

Update.....

I learnt,

Rather than push the shaft through from the motor side of the bike and hope the water seal will be Okay with that  .....

Work the seal down the shaft gently as you go.....

The key word gently.....

Order of Assembly.


 
A little alcohol to clean the surfaces...... What....?




I use ThreeBond  1211 as a sealant.
some may have a problem with this however it works...

hey guys. I fitted the replacement kit over the weekend. My 89 K100 had the original boot and rusted round spindle. Luckily I had bought a replacement newer type in the event this happened. 

All was going great until I tried to tighten the shafted clog back into the pump unit. It got so far with probably 1cm or so to go and just wouldn't engage any more. The bolt I was tightening at one end would just spin and not drawer in the shaft anymore. 

Then even though I read not to force it on I had a moment of unclarity and did... breaking the new spring mechanised seal... so I've ordered another water and oil seal and will attempt take 2 over the weekend. 

Does anyone have any tips for getting the final length of the shaft to feed through so the clog sits flush with the housing? I did try using a longer screw but that didn't work either. 

Cheers

Hi, 

I don't think any if us get any with doing this job with one set of seals. It takes that $70 sting to slow down..... 

It's been awhile since I've done this dance however, the second time I did it I remember a flash of enlightenment.... 
I remember sharing it with Charlie. However, the bad news is I can not remember.  It was the reverse of what I did the first time. In that rather than pushing the shafts through, let the case move up the shaft, (I know that doesn't make much sence) however it was something like that. 
And, of course you oil the lips of the seals and shafts in order to facilitate a smooth install. 
If you find your becoming impatient, remember you can always down tools and come back to it. (And save $70).

I hope this helps.

IIRC I was a bit abusive and put a deep socket over the spindle that was the same outside diameter as the pump seal. I then turned the whole lot upside down so that the gear was on the bench (on a towel actually) and effectively drove the pump casing onto the gear. Inevitably the gear hits the back of the pump and won't turn, but at this point a smart tap on the spindle with the hammer will produce enough clearance to turn the gear without it binding on the engine and without destroying the seal (as you are punching the spindle into the seal). If you go too far the other way, see above re: towel and socket!

Yep, what Dai said....

Thanks guys. I actually did end up driving the shaft on the cog into the casing by turning it upside down and applying pressure. I think it seperated the seal with the spring mechanism however so am a bit hesitant about trying that again. If I pushed the cog there was no springy pushback...

The cog does fit flush with the housing but I think the seal has broken in the process as there's backwards and forward play for half an inch where the shaft/cog can be pushed out of being flush against the housing. 

I'm not sure whether the cog turns when it is flush. Will have a look in the week when I get to the garage. 

Day, where abouts did you tap with the hammer to get the cog to turn? I'll try this before ripping out the existing seals to see if it works.

Looking at the picture earlier in this thread I didn't have item 3 counting down from the pump (inbetween the cog and the seal)... my pump for sure has not been updated since the day it rolled off the production line in 89. Hopefully this sits elsewhere in the pump and I haven't paid enough attention 

Cheers

Hi, 

The photos I posted are from a K11. 
A part from the amount of teeth on the cogs, I'm not sure if there is difference.

Yep, you've sent the seal to the great bin in the sky. The trick is to use a socket that is the same O/D as the seal housing; you're then driving the seal housing which is driving the casing which... etc.

Ah so put a deep socket from the side the bolt screws in (where my new type spindle goes) pushing on the head of the seal driving the entire casing down onto the shafted gear?

Thanks guys 

I am concerned by an oil leak at the front of my 1983 K100. I have washed the area down and will watch it carefully but assume it is coming from the water/oil pump.Does not appear to be any coolant leak though, just oil though not enough to make a puddle on the drive.

I have read that these earlier bikes have a pump shaft which fails if a repair is attempted and that I should seek a later model shaft.I guess the best plan is to drop the front cover off the pump to check what is in there.

Is it likely I can track down a second hand pump suitable for fitting a new repair kit to? Anyone  with one to sell?

Hi mate, a quick reply as I'm out and about. 
I didn't see what country your in however in Australia the rebuild seals cost approx $60US. So rebuilding the pump is a good option. However, please be advised to read all of the above in detail... I will be very interested if you get it right 1st go.... Not many of us do - have or have done.... Hit me up if you need more info. Plus others will be looking over your shoulder as well.

That looks like an oil-leak-only. The front cover has no gasket, so it's a fair bet that the oil is leaking passed the gasket cement. Answer is to pull the cover, clean the crappy gasket goo off and apply some new stuff. The catch..? Make sure you have an impact driver to hand because it's a fair bet that one or more bolts may be seized in.

Thanks Dai and Mark.

I will pull it as suggested. Agreed, there is no coolant leak visible. I suspect however that it will be an original 1983 impeller shaft with a nut so will still hope to track down a later model shaft for a rebuild.

Ummm, Sydney is my location, not my name (Sydney in Australia that is).

Michael

If your just trying to solve an oil leak... most likely its between the pump body and the sump ...
no need to withdraw the pump shaft Other  to gain access to the bolts to remove the body and from memory nothing behind the impeller that needs to be removed to pull the body off

should be doable without too much drama   
Just use a good sealant on impecably clean surfaces with just a smidgen of sealant to do the job

good luck