2004 RT, alternator belt replacement. . .

[RT Pilot]

OK. . .I've got an 04 RT, built on 11/03, which is indicative that it has the newer-type alternator belt installed. I'm at almost 39,000 miles on the original belt and I know it needs replaced and I'd like to do it myself, but the required tool to do the job costs over $230.

 

I've researched this extensively on the net and by calling some dealers and the tool required does NOT measure tension, it measures DISTANCE between the pulleys. I've been erroneously directed to buy the cheaper ($40) TENSIONING tool, but I'd rather do this job the right way if possible and use the correct tool. I've searched the 'net for an aftermarket tool for this job and have been skunked so far.

 

Is anyone familiar with the "official" alternator belt pulley distancing tool?

 

Can anyone provide the specs for this tool so that an aftermarket alternative can be found or fabricated?

 

Does anyone have this tool, so that I could possibly borrow it for this job? (I'll pay shipping both ways).

 

Would tensioning the belt with the older / cheaper tool work just as well?. . .I get the impression that some of the dealers I spoke with use the old tool / method anyway. . . .I don't want to pay a dealer to do this work if they aren't going to use the correct tool.

 

Thanks in advance for your input!

 

Rob

RT Pilot

[Richard_D]

All you need the the belt tensioning tool. I have one you can borrow. You can also do it without tools by tightening the belt so you can just 1/4 turn it.

[ElevenFifty]

replaced original at 32K - is was trashed...

 

replaced that at around 60K - the belt showed no signs of wear ...

 

just examined the belt at 88K ... the belt looks new, no cracking, no wear signs at all. NEVER used any tension measuring tools, just appropriate levers and the 1/4 twist method.

[barryNmarin]

I agree, no magic (expensive) BMW tool needed. I use the quarter turn (90 degrees) tensioning method and it works great on my 04 RT. The KISS method works well on alternator belts.

[Ken H.]

Seconding (or thirding, fourthing!) the others, the distance measuring tool you are referring to is really a solution looking for a problem. Use the regular BMW tool and tension, or even the ¼ - ½ belt twist method – it will be fine.

[Starfighter]

about time to do mine also

(since I have to remove the crash bar subframe for machining)

My question are:

1. Do I have to loosen or remove the exhaust and if so how to prevent bolt breaking)?

2. where do you cut the cover to make future belt changes easier ?

Thanx

[Ken H.]

1. Not needed - remover the 'upside down shark fin' small lower faring piece on the right side and the cover can be wedged out.

 

2. Right through the center of the logo, but personally I don't like that approach.

[RT Pilot]

Thanks for all the replies. . .it sounds like the old-fashioned method has worked for everyone and that's what I'll go with.

 

Rob

RT Pilot

[Richard_D]

I didn't cut my cover but I went to Ace hardware and bought a rubber grommet that is the same size as the round logo on the alternator cover. They also had a black plastic plug that fit very tight in the rubber grommet. Presto !!!! The round logo is exactly where the nut is.

[pmfranke]

The belt requires enough tension not to slip during load and not to tight to cause bearing failure . After running 500 miles or so should be checked for looseness . Some stretching may occur.

[RPG]

I just used the "free tool" I had laying around in my tool box. I'm missing something here. Isnt' it just a fastener that's used to raise the altenator in relation to the engine, thereby tightening the belt. And once tightened and locked down I make sure that I can only twist the belt up to about 90 degrees.

 

40k on the original belt on my '04RT so I think I'm doin' it right......

 

RPG

[Fugu]

. Some stretching may occur.

 

After about the third time I screwed with the cover to find the belt was still plenty tight I quit doing that.

 

I always carry a spare belt because stuff happens, but I don't use any fancy tensioner tool or re-check tension.

[Ken H.]

Isnt' it just a fastener that's used to raise the altenator in relation to the engine, thereby tightening the belt.

Yes, but as the OP mentioned, mid-2004 the belt type and method was changed.

[T__]

OK. . .I've got an 04 RT, built on 11/03, which is indicative that it has the newer-type alternator belt installed. I'm at almost 39,000 miles on the original belt and I know it needs replaced and I'd like to do it myself, but the required tool to do the job costs over $230.

 

I've researched this extensively on the net and by calling some dealers and the tool required does NOT measure tension, it measures DISTANCE between the pulleys. I've been erroneously directed to buy the cheaper ($40) TENSIONING tool, but I'd rather do this job the right way if possible and use the correct tool. I've searched the 'net for an aftermarket tool for this job and have been skunked so far.

 

Is anyone familiar with the "official" alternator belt pulley distancing tool?

 

Can anyone provide the specs for this tool so that an aftermarket alternative can be found or fabricated?

 

Does anyone have this tool, so that I could possibly borrow it for this job? (I'll pay shipping both ways).

 

Would tensioning the belt with the older / cheaper tool work just as well?. . .I get the impression that some of the dealers I spoke with use the old tool / method anyway. . . .I don't want to pay a dealer to do this work if they aren't going to use the correct tool.

 

Thanks in advance for your input!

 

Rob

RT Pilot

 

 

 

Rob, not exactly sure when BMW went to the free-wheeling alternator pulley & elastomer belt but I’m pretty sure your bike has the later (stretch type) elastomer belt (like the 1200 hex uses).. The belt tensioning is quite different on the later 1150RT’s using the elestomer belt than the early 1150RT’s using the conventional fiber belt as it (the late 1150) uses fixed pulley distances to control belt tension on an elastic stretch type belt..

 

I have only done 2 of those elestomer belts on the (late) 1150.. On the first one I did it by measuring the distance between upper & lower pulley flanges BEFORE removing the original belt.. I don’t have my notes handy here but if memory serves me (not as good as it used to be) it was something like 4-1/2” from upper pulley lip to lower pulley lip..

 

On the second belt (different bike) I simply marked the alternator original position then installed the new belt,, then pried under the alternator to put it (the alternator) back to the markings.. (this seemed work pretty good & at least put the same pulley spacing distance back as was there to begin with)..

 

I couldn’t convince myself that using the ¼ twist was an accurate method on the stretchy elastomer belt as it has a lot of stretch to it..

 

After now doing a couple of 1200 hex head elastomer belts (no alternator adjustment available) I believe the next late 1150 belt I do I will just use a piece of plastic & roll/stretch the belt on the pulley like you do on the 1200 hexhead.. I can’t say for sure that this will work until I try but if you want to try the roll on method go over to the hexhead forum & search for belt or “belt install”..

 

Added note: I believe if your 2004 1150RT has the late ELASTOMER stretch belt there will be a little raised tangle on the lower belt cover (not 100% sure this is true across the 1150 line but some seem to have it anyhow)

 

Twisty

 

[RT Pilot]

Thanks for the detailed reply Twisty. . .I'm always glad to see your comments and advice. I just finished installing the new alternator belt. . .and like most jobs I've never done before, I ran into some unforeseen issues.

 

First off, my bike was built in 11/03 and therefore specs the newer elastamer belt, BMW part number: 123 176 818 41.

 

NOTE: There was NO raised triangle anywhere on the belt cover that signified the newer belt type.

 

After removing the cover, gas tank etc. I noted the following: that the existing (old) belt was very tight. I could twist it 1/4 turn with a fare amount of effort. I also noted the position of the alternator within it's mount and scribed a line at the top mounting bolt so I could use it a reference point. I measured the distance between the pulleys and it was about 4 5/8".

 

I removed the existing belt by loosening the alternator mounting bolts and slipping it off the pulleys. Comparing the old belt to the new belt, it became apparent that the new belt was somewhat smaller in circumference, but the new belt had the same part number as the old belt. I'm assuming that the belt will stretch some over time and miles.

 

I installed the new belt by lowering the alternator to it's lowermost point in the mount, looping it over the alternator pulley and then "pushing" it on to the engine pulley whilst my spousal unit rotated the rear tire (in sixth gear). It should be noted that even with the alternator at it's lowest point the belt went on TIGHT!

 

Now the fun part. . .Richard_D was kind enough to loan me the tensioning tool that's specified for the older belt type. I decided to first try using that tool, in the hopes that it would bring the tension within the ballpark. Following the instructions in the factory manual for tensioning the belt with this tool, it quickly became apparent that the torque spec'd for that tool (8 nm) would be insufficient to tighten this newer type elastemer belt. After increasing the torque value to 10 nm and then 15 nm with no appreciable gain in tension, I removed the tensioning tool and noted that I'd over-torqued it and ruined Richard's tensioning tool--crap! After using Richard's tool, the alternator was still resting on the engine case--it hadn't even lifted it at all, and the belt tension was not nearly as tight as the original belt, judging from the somewhat subjective 1/4 turn test. . .so, to summarize, DO NOT USE THE OLD-STYLE BELT-TENSIONING TOOL on the newer style elastemer belts--it won't work.

 

Onto Plan B. . . .I decided that since I didn't have the $242 new-fangled pulley distancing tool, and the wife reminding me that she didn't see one in my future, I realized that I had to go "old school" on this project. I grabbed a big, mamma jamma screwdriver and put increasing tension on the belt by prying the alternator upwards from the engine case and then tightening the mounting bolts. After a couple of tries I was able to tension the belt to the same subjective spec of the 1/4 belt turn test that I'd noted earlier before this little adventure in wrenching started.

 

After tightening all the alternator mounting bolts (you will NOT be able to put a torque wrench on the top one because of the inconvenient location of the front shock absorber), I checked the location of the alternator with respect to the marks I'd made earlier--the alternator is about 1/4 inch lower on the mount than with the old belt, although I'm confident that the belt tension is pretty darn close to where it should be. I've made a note in my maintenance log to check the tension again in 6000 miles.

 

As far as the old belt condition, in my opinion it looked like it would go another 38,000 miles--there were no visible cracks whatsoever and the dimensions were identical to the replacement belt, excepting the circumference, which obviously had stretched over time / miles. I'll be keeping the old belt for a spare.

 

After putting everything back together, I did a short ride around the neighborhood and turned on all the electric stuff to "load up" the alternator--no flickering lights, no warning lights, no squealing (except for my wife, because I took all afternoon to do this!), even at idle.

 

I'm glad I did this maintenance myself. As always, I've learned much and feel better prepared in the event I need to deal with this issue while on the road. It's been said that you always somehow pay for your education and this was no different--I'll be buying Richard_D a new tensioner tool, but the adventure in learning was worth it. . .and it's still cheaper than taking it to the dealer.

 

If anyone has any questions, feel free to post them here--I've learned much from other forum members and I'm happy to be able to give something useful back to the group!

 

Rob

RT Pilot

[T__]

Rob, sounds like you got it pretty close.. Yes, I usually pry under the alternator as it takes a LOT of effort to stretch that new belt.. I can see where the old tensioning tool or double nut would not do the job (not even close to enough force)..

 

On your new installed position-- I think you should have matched the original alternator marks up as that new belt is properly tensioned with pulley spacing not ¼ twist or by feel.. They are tight as a bow string when first installed.. You are pretty close at only ¼” off so will probably be (OK).. That should leave you about 1/8” closer pulley spacing than my 4-1/2” setting..

 

After you run it a while you can get that extra ¼” pretty easily as it will stretch out a little..

 

Twisty

 

[RT Pilot]

Twisty. . . I tried to get the alternator back on the mark I made, but I was starting to tip the bike off the center stand by prying (lifting the bike)--I assumed that my dealer (who did the first couple services) must have re-tensioned the factory installed belt at some point after it stretched. I'll be checking the tension again at the next service interval to make sure it's still good. I guess I'd rather have the belt not quite tight enough, rather than risk too tight and ruining the alternator. . I can always re-adjust the belt.

 

I can't imagine that dealer techs use the newer tool. . .the ones I called didn't seem to know what I was talking about when I described how it worked. . a few of them tried to sell me the old tool. . .based on that I'm guessing that most dealers use the old-school method that I used anyway. . .

 

Thanks for your input. . .

[T__]

Rob, I’m wondering if the dealer can/does use the special belt installer from the hexhead & roll the belt on without loosening the alternator.. On the 1200 hex the alternator is fixed in position (can’t be moved) & the elastomer belt is rolled on the lower pulley by using the special tool (like special shoe horn).. I use a piece of plastic in place of the over priced BMW hexhead belt tool & while it is a real pain the belt does go on with little fanfare..

 

Twisty

 

[RT Pilot]

Hey Twisty. . I just had a thought. . .it seems like a simple tool could be devised that would fit between the pulleys that could effectively spread them apart until a certain distance is achieved. I would envision the tool having curved ends that would "cup" the inner sides of the pulley and some sort of threaded bolt mechanism that you could open (spread) or close with a socket or wrench. Have you ever seen anything like that? It seems that you could precisely set the pulley distances, set the mounting bolts and then remove the tool. Am I overlooking anything?

[T__]

Rob, yes I have seen a similar tool.. It had as you said a curved piece of steel on each end with a rubber pad glued to the curved steel.. It had a steel tube welded on one pad (about the size of ¾” electrical conduit but a little thicker wall tube,, the other end had a length of 3/4” all-thread welded to it.. It was a fair amount longer than what’s needed on the BMW application but the concept was the same.. Had a nut on the all-thread that tightened against the tube & expanded the “pulley spreader”

 

We used to have it in the shop where I worked & it was used as you would imagine to tension fan belts of multi-belt systems.. It was a shop made tool & I don’t remember who built it (far as I know it was built before I worked there) ..

 

Be easy enough to make one but so far it has been easier to put the BMW belt on using a pry bar & marked alternator position than making a tool..

 

I still think I am going to try rolling the belt on like on the 1200 hexhead on the next one I do..

 

Not many of those late 1150 elastomer belt engines out there so I might not ever see another one..

 

At least with you having a well used belt it should go on real easy if on the road replacement needed,, probably better carry along emergency belt than a new belt..

 

Twisty

 

[AndyS]

.......If anyone has any questions, feel free to post them here--I've learned much from other forum members and I'm happy to be able to give something useful back to the group!

 

Rob

RT Pilot

 

I replaced my elastomer belt some time back - way after the recommended milage - because I felt guilty leaving it on even though it looked perfect.

I popped the old one off, and like you, even with the alternator at it's bottom stops, I was concerned about the force required to fit it. I removed 2 of the alternator bolts allowing it to tilt - this aided fitment. Anyhoo, I fitted the new belt and replaced the alternator bolts and was really concerned about the shaft tension being applied to the alternator. I contacted my belt suppler who assured me they sent me the right part, but I decided to try a replacement belt. This too was bar taught. In the end I was uncomfortable stretching the belt any tighter, and have lived with a belt which I can impart a small twist to. It has to my knowledge never slipped, so I'm reasonably happy. As an engineer, I am uncomfortable with the amount of tension being applied just to drive an alternator.

Andy

[RT Pilot]

Hi Andy. . same here. . .that's why I was hesitant to utilize the method that Twisty outlined above (leave alternator in original position and "shoehorn" the new belt on).

 

It seems like the tension could be excessive and might cause premature wear of the alternator bearings, although he didn't report any issues with doing it that way. Although the belt is a stretchier material, I still think the 1/4 twist method of checking tension will get you in the ballpark without risking over-tightening--I don't mind checking the tension later-on, and re-tightening as needed.

[jblaze5779]

There's a tool available at Napa called "the cricket". I use it for tensioning the serpentine belts in my jeep and saturn. I imagine it'd work for this application as well. It's basically just a gauge for measuring the tension along the belt.

 

I think it was $24.