Hi,

I've just finished converting the front brake on my M21 to hydraulic operation and have a 10page write-up to go along with it. I really enjoyed the project & wondered if anyone was interested in reading about it?

Let me know, I'll e-mail a copy.

Cheers

Ben

email (option): mad_king_soup@hotmail.com

Yes please - I'm always willing to learn something new!

Doesn't the fork bend a bit when you jam the anchors on hard?

ChrisJ

email (option): chris.joy@btinternet.com

Ok Chris, I've sent it. It's attached via SkyDrive so hope it arrives ok.

Cheers,

Ben

email (option): mad_king_soup@hotmail.com

Hi Ben

Would like to see - yes please

Can you PDF it ?

Best regards

Jo'b

email (option): Jonnyob1@googlemail.com

Ok John, I've PDF'd it for you.

Cheers,

Ben

email (option): mad_king_soup@hotmail.com

Write-up received and read.

A very interesting DIY project which demonstrates Ben's ingenuity. I'm slightly concerned about the strength of the cross-piece on the shoe pivot though. Work up to road speeds gently, Ben.

ChrisJ

Thanks Chris!

Good point. There's definitely room for further development. (Aswell as thorough testing!) Maybe I'll look into getting a one-piece pivot machined up at a local engineer's. Once the bike's on the road I think I'll build up slowly as you suggest and strip & inspect it a few times too!

Cheers

Ben

email (option): mad_king_soup@hotmail.com

Hi Ben,

I have e-mailed you.

It would be great to have a PDF also.

Thanks,
Noam.

email (option): noam10@gmail.com

Could you PDF a copy to me, too? Thanks. Or perhaps you can post it on the technical section, as I'm guessing you'll get a lot of requests.

email (option): jonny.rudge@verizon.net

Good idea But it seems that Henk has a huge backlog of items to be placed there

email (option): viaconsu # planet dot nl

Hi Ben,
Could you please e-mail me a copy also?
Thank you,
Ray

37ariel at gmail dot com

I have sent a copy to Henk but like Hans says I imagine he's a very busy man!

I'm more than happy to e-mail copies to people. Especially if I recieve constructive feedback as there is always room for improvement!

Cheers

Ben

email (option): mad_king_soup@hotmail.com

Hi Ben..I'd like to take a look...Ian

email (option): ian@wright52.plus.com

Hi ben

Thanks for that

Will study time permitting this week

Well done for undertaking & sharing on the forum

Best regards

Jo'b

email (option): Jonnyob1@googlemail.com

Got the PDF. Truly ingenious. However, I share the concern about the pivot cross-piece. Keeping in mind Newton's third law of motion (for every action there is an equal and opposite reaction) your statement that "all of the braking force will be applied to the other side" is not entirely accurate. The cross-piece seems to be the weak link in the system, as it will need to withstand a force which is equal to that which the wheel cylinder exerts on the other side of the shoes. This force will now be higher than that which was previously exerted by the non-hydraulic system - which is the point of the hydraulic conversion. As such, I question whether the cantelevered ends of this piece will be sufficiently robust to avoid bending the cross-piece with repetitive applications of the brake. I surmise that closing the loop with a flat piece, such that the now-cantelevered ends get connected, should improve reliability. Better yet if you can find a way to replace it with an adjustor, not only because it will make it less likely to bend but because it will permit adjustment, so that the shoes will contact the drum over a larger surface area.

Another possible problem you may wish to think about is the turning moment that this piece will be called to withstand, i.e., that force of the brake shoe which would tend to rotate the brake shoes in the same direction that the brake drum is turning. This force would tend to bend the ends of this cross-piece piece toward the drum edge on one end of the piece and away from the perimeter (i.e., toward the axle) on the other end. This force is negated in the original setup by the fact that the ends of the shoes which rest on the pivot point are partly circular and, therefore, cannot move without actually breaking the pivot pin or the ends of the shoe. In your setup that force is only opposed by the thinnest parts of the cross-piece. I don't know whether that would be sufficient or not, just a point to keep an eye on them during your testing period.

Please post your real-life results once you get the bike on the road. For some time now I have been mulling over the prospect of replacing the front brake with a disk brake system. But my understanding is that the front suspension is not sufficiently strong to withstand a significantly higher braking force, and that the front fork spring will collapse when such higher braking force is applied. Obviously, that is a different project than yours and one in which originality is not an issue. However, yours will provide a higher braking force than the original and I would sure like to know whether the collapsing spring theory is, in fact, a problem in real life. (Sorry, but when you break new ground others are liable to use your work as a guinea pig.)

email (option): jonny.rudge@verizon.net

Thanks for the encouraging feedback, much appreciated!

John, you Noam and Chris have all mentioned the weakness of the pivot & I totally see your point. I Think I will look into a beefier version. I was thinking along the lines of a cross piece made from 10 or 12mm bar with slotted ends to fit the shoes and solidly mounted. An adjuster is also an excellent idea and something I have been thinking about as although the braking action is good there is a touch of 'low pedal' to use a car term.

I'll try to post any developments, aswell as how it performs once on the road (whenever that might be!!)

Cheers

Ben

email (option): mad_king_soup@hotmail.com