R100RS rear brake hose / grommet incompatibility

'80 R100RS with Brembo rear brake. I bought a new hose and the grommet that holds the female end of the hose to the "holder" clamp that screws into the tapped hole oin the frame near the rear left of the battery box.

The original hose's female end is 13mm OD. The new hose's OD is 16mm. But the grommet did not increase in size. I got new hoses from two different sources, and looking at pics from other sources they're the same hose, so it's not a 1-off.

The problem is that the female end of the hose will absolutely not fit into the grommet when the grommet is installed into the ring-like "holder". I only see two options:

1) grind carefully the OD of the hose to 13mm.

2) try to open up the grommet using a really sharp blade.

But before I do either of those workarounds, I wanted to check and see if anybody else has run across this issue.

Thanks,

Eric Z

You should contact the place where you bought the rear hose. I bought Speigler lines and they fit my 81 R100RT rear grommet fine.

PAS said:

You should contact the place where you bought the rear hose. I bought Speigler lines and they fit my 81 R100RT rear grommet fine.

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Would you be able to measure the OD of the female piece in the grommet? Like I wrote, I have two hoses, from two different vendors, and they are identical, and the grommet from both of those vendors are also identical and incorrect. And the MaxBMW fiche shows the exact same hose as I have, as does the Motorworks.uk site.

These are the rubber hoses btw, so maybe the Spiegler ones are indeed 13mm. If I knew that for sure I would bite the bullet and buy one but I'm done with trial and error.

ezwicky said:

Would you be able to measure the OD of the female piece in the grommet? Like I wrote, I have two hoses, from two different vendors, and they are identical, and the grommet from both of those vendors are also identical and incorrect. And the MaxBMW fiche shows the exact same hose as I have, as does the Motorworks.uk site.

These are the rubber hoses btw, so maybe the Spiegler ones are indeed 13mm. If I knew that for sure I would bite the bullet and buy one but I'm done with trial and error.

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I cant measure mine (Speigler) that part is inside the grommet. Contact Max and have them measure it. Oddly Speigler shows your bike have an ATE rear caliper, which is wrong. Speigler sells S.S. braided lines and yours would take the same as my 81 R100RT. Where did you buy the two hoses?

I bought them from EME and Boxer2Valve. I can see from the pics at Max and Motorworks that they offer the same hose.

I'm also thinking about enlarging the ring of the holder. I have a new holder and the original one, so I can alter one of them without feeling too bad about it.

Vendors

EME and Boxer two valve have good customer service. Call them and they will help you out. Either they messed up and sent you the wrong part or you messed up and ordered the wrong part. Either way, once you "modify" it, it is yours for better or worse.

Brakes are one thing I NEVER cobble together, if a part does not fit right, it goes back or I ensure I get the right part to do the job. St.

STEVENRANKIN said:

EME and Boxer two valve have good customer service. Call them and they will help you out. Either they messed up and sent you the wrong part or you messed up and ordered the wrong part. Either way, once you "modify" it, it is yours for better or worse.

Brakes are one thing I NEVER cobble together, if a part does not fit right, it goes back or I ensure I get the right part to do the job. St.

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I get it, but looking at five different ordering sources, the part is the same everywhere. Both the grommet and the hose. Must be a new thing because nobody so far has had this issue.

I'll talk to Norm at EME today. I've bought 90% of the new parts for the RS project from him. But I don't expect him to have a solution, nor any other vendor, because the parts are-what-they-are....

Maybe this will help.
https://brook.reams.me/bmw-motorcycle-rebuilds/1983-bmw-r100rs-rebuild-project-index/34-bmw-1983-r100rs-install-rear-brake-system/

PAS said:

Maybe this will help.
https://brook.reams.me/bmw-motorcycle-rebuilds/1983-bmw-r100rs-rebuild-project-index/34-bmw-1983-r100rs-install-rear-brake-system/

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Brook's site is my go-to. I have it open on my garage laptop perpetually. His method does not work for me. He must have been using the older 13mm hose.

Norm at EME will take the rubber hose back. The SS line he sells has the proper 13mm OD so I ordreed that. He also made a note on his catalogue as to the 16mm OD of the rubber hose to caution future purchasers.

Pictures

Pictures on the web pages don't really tell if there is one or more part number units available for your bike. I am really surprised Norm was not able to help you solve your problem. If everyone is stocking the same part, how is it you got the wrong part?

Have looked at a good online microfiche such as Max's or another, to look to see if there is more than one part number listed for a hose?

I am not sure if 80 or 81 was the cross over year for changes on the bikes. I could explain things. As for an ATE rear brake, I have never seen one, only the Brembo.

Can you take a bunch of pictures and share them? It may make things clear. St.

Here's what I'm talking about. Yes I exhausted every online resource I could think of. The pictures of every hose match exactly the one in my pic. The OD of the hose increased, the corresponding dimensions of the grommet and holder did not.

Norm said he was going to have a word with his suppliers.

No word back from Bill Plam yet.