11 BMW 1973 R75/5 Replace Cam Shaft Seal

This is strong evidence that the cam shaft seal needs replacing. 🙂

Leaking Cam Shaft Seal

Leaking Cam Shaft Seal

This is a fairly straight forward repair. That said, care is needed to avoid scratching or damaging the camshaft when removing the old seal.

Parts List

This is the parts list. I also replaced the points and condenser.

Part # Description Qty
11 14 1 261 193 Cam shaft seal 1
65 61 2 300 654 Cam Housing Gasket 1
12 11 1 243 555 Points 1
12 11 1 351 564 Condenser 1

Remove Points and Timing Plate

I removed the existing points assembly, and will replace it with a new set of points. Their is a single machine screw holding the points shown in the top right of this photo at the 1:00 position right next to the points.

Points Assembly

Points Assembly Mounted on Timing Plate

This exposes the timing plate which is attached with two longer machine screws at the 12:00 and 6:00 position. I remove the 6:00 screw first so I can detach the points wire from the metal tab securing it. Then I disconnect the points wire from the condenser and removed the wire out of the long rubber sleeve. Then I removed the 12:00 screw leaving the timing plate free for removal.

Points Plate

Points Removed and Timing Plate Ready to Remove

Remove Camshaft Seal

I twisted the timing plate to get it loose to expose the camshaft seal, shown here as a black seal around the camshaft. The seal on the /5 is not very large. The black bits at the bottom of the casting came from my attempt to remove the seal with a pick tool, which failed as it only shredded the rubber seal.

Old Seal

Old Seal

Lisle_5660AdjustSealPuller

Lisle 5660 Adjustable Seal Puller

Next, I used a heat gun to head the metal housing around the seal and then very carefully inserted my adjustable seal puller next to the camshaft to carefully pull the seal out. I don’t want to pry against the camshaft and I don’t want to scratch the outside of the boss the seal mounts into. It popped out.

 

Shaft Seal Puller

This lead me to look for a seal puller for small seals. I found a very promising one, Lisle 58430 shaft seal puller. It’s available at some auto parts stores, but I got mine from Amazon.

Lisle_58430SealPuller

Lisle 58430 Shaft Seal Puller

I also found a YouTube video on how it is used and that sold me on this type of puller. I ordered it for the next time I have seals to pull. I think this design reduces the risk of gouging or scratching the boss and the camshaft.

 

 

 Install New Camshaft Seal

I used brake cleaner to clean the camshaft and the boss the seal goes in to be sure everything is nice and clean and there are no sharp edges on the boss. A 5/8 inch spark plug socket fits the new seal nicely and it’s what I used as a drift to install it.

5/8 Inch Spark Plug Socket Fits Camshaft Seal

5/8 Inch Spark Plug Socket Fits Camshaft Seal

I put the seal in the hole and squared it up, then put the 5/8 socket over the camshaft and gently drove it home with a plastic mallet.

Driving Cam Shaft Seal

Driving Cam Shaft Seal with 5/8 Inch Spark Plug Socket

Camshaft Seal Installed

New Camshaft Seal Installed

Install New Points and Condenser

I replaced the old condenser with the new one. Then I snaked the new points wire up the long rubber tube and attached it to one of the spades on the condenser. Their is a second wire from the back of the timing cover that goes on the other spade.

I find adjusting the timing plate with a screwdriver on the two longer machine screws requires a large blade and invariably the slots get chewed up. So I visited my local ACE Hardware and got two Allan head cap screws, M4 x 0.7 x 10 to replace them.

Original Points Screw (bottom) & Allen Head Replacement

Original Timing Plate Screw (bottom) & New Allen Head Cap Screw Replacement

After attaching the cleaned up timing plate with the new Allan head cap screws, I installed the points with the original shorter machine screw. Then I inserted the timing came and attached it with the 10 mm nut being careful to not over tighten the nut. Now, I can adjust the timing plate with the timing cam and centrifugal advance weights on the cam shaft with a small Allan wrench. It will be a lot easier to adjust the timing and I won’t have rounded slots on the machine screws to contend with.

New Points and Allen Head M4x10 Cap Screws

New Points and Allen Head M4x10 Cap Screws

13 thoughts on “11 BMW 1973 R75/5 Replace Cam Shaft Seal

  1. Pingback: 1973 R75/5 Rebuild: New Oil Pan Gasket and Camshaft Seal | Motorcycles & Other Musings

  2. Pingback: 1973 BMW R75/5 Rebuild: Replace Alternator Brushes and Front Crankshaft Seal | Motorcycles & Other Musings

  3. OK- missed the part about heating the seal before pulling. The Lisle tool just pulled the inside of the seal out and now I am stuck with the outer perimeter which seems glued in place. I will try heating and then pulling, But was considering a chisel to notch and try and spin the seal to loosen. Be sure to heat the old seal so you don’t have my issue! Also, what about freezing the new seal to make it easier to install?

    • HI Roger,

      Sorry about the problem getting the seal to come out. Heating the case around the seal makes a big difference in getting it out. Putting the new seal in was easy with a 5/8 spark plug socket that fit over the cam shaft and rested on the outside of the seal. I didn’t need to chill the seal or heat the housing to drive it in.

      Best
      Brook

      • How much heat? How long? I used a small butane torch for 3-4 minutes. I have a paint stripper gun I can use.

        There are issues with the motor being in the bike as it is difficult to work around the frame and hard to see,etc. I have used a lighted 4″ magnifying glass and still cannot see inside very well.

        • Hi Roger,

          I used a heat gun and heated the metal around the seal for a minute or so. The rubber smoked a bit and then I used the Lisle shaft seal puller (red handle) and put the arm under the seal toward the outer edge. I levered the seal, rotated the arm about 30 degress, levered and continued until it started to move.

          I’m sorry this one is being so stubborn.

          Best.
          Brook.

          • Roger,

            This is one of those situations where the advice “Endeavour to Persevere” is appropriate. You’ll get this problem solved.

            Best.
            Brook.

  4. Hi Brook, How did you know the cam seal was in deep enough? It looks like it is deeper than “flush” with the outer timing-cover surface.

    Thanks and Merry Christmas,

    Eric Z

  5. Hey I’m currently installing a electronic ignition on my R75/5. I sadly broke the 10m nut and I was wondering if you could tell me what kind of nut it is?

    I’ve tried with both M6 and M6 links nuts without luck.

    • Hi Kristian,

      I’m sorry to hear about your troubles. As far as I know, the nut that secures the advance mechanism on the end of the camshaft is a standard M6 nut. It’s possible the nut you have is not the proper thread pitch. The nut is a standard M6 x 1.0.

      You don’t say how the “nut” was broken. It is possible whatever happened also damaged the threads on the end of the cam shaft. If so, it’s possible that using a die, M6 x 1.0, to clean up the threads on the end of the cam shaft will fix the problem. BUT BE CAREFUL. You don’t want to damage the end of the camshaft, bend it or break it.

      I hope this helps.

      Best.
      Brook.

      Best.

Leave a Reply

Your email address will not be published. Required fields are marked *