Eccles' front brake improvement 2023

[Sidecar Bob]

Some of you have seen my thread asking about using a car caliper on Eccles (CX650E based winter sidecar machine that is now mostly GL500)
http://www.ngwclub.com/forum/viewtopic.php?t=78248

After a bunch of messing around (including buying a set of aftermarket ATV calipers, finding out they didn't have piston boots like Honda specced and sending them back and many hours squinting at pics to try to see if they showed boots) I ended up buying a set of used calipers from an '80-83 GS750L. I am only going to use the right one but I couldn't find a suitable right caliper for less. At least I'll have a spare set of pads

GS750L caliper pic from eBay 1.jpg (88.59 KiB) Viewed 1064 times

GS750L caliper pic from eBay 2.jpg (77.32 KiB) Viewed 1064 times

When I got the GL500 (2 winter bikes before Eccles) its master cylinder wasn't worth rebuilding so I obtained a suitable good used master for it. That one didn't have a brake light switch so I modified the GL500 lever and the master to work together with the switch from the GL's original master, put a kit in it and used it for 5 years on the GL500, part of a year on the CB750SC and 7 years on Eccles.
When it needed a rebuild a lot of people on cx500forum were replacing their master cylinders with ones sold on eBay for the CB400 (most likely the "Super Four" model). I made the mistake of ordering the lowest priced one I could find and a year later its rubber parts went bad so I bought 2 more from a known good seller. The first one went on Eccles right away and I eventually got around to installing the 2nd one on Mr.H.
I made the mistake of ordering both with the same 16mm bore. That works fine with Mr.H's pair of 2 piston calipers but with Eccles' single 2 piston caliper it significantly reduced the lever travel. I got used to it but it has never been right.

Because of that I was particularly concerned about the new caliper's effect on master to caliper ratio. The current caliper's pair of 30mm pistons have a total area of 1413 mm² and the GS750L caliper's single 38mm piston is only 1134 mm², which would make things worse. I briefly contemplated changing to 2 discs & calipers but the more I thought about it the less I really wanted 2 front brakes on a sidecar outfit that will be used in the winter (lock the front brake and the sidecar's inertia pushes you into the oncoming traffic). In the end I decided I'd be better off staying with one disc & caliper and changing to a smaller master cylinder.

So last weekend I ordered a 12.7mm master cylinder (aftermarket for ATC250) and a kit for the caliper that includes the boot & seal and a new piston. The master cylinder came this week; It looks pretty good for a $20 CAD master cylinder but I have not tried it yet so I cannot vouch for it. Unfortunately I really won't know for sure whether it is good for at least a couple of years and who knows if the same seller will be selling the same item from the same supplier by then?
https://www.amazon.ca/dp/B09YTZX8D7

My only problem is the geometry of a dogleg lever. Although pics I find online of original ATC250 master cylinders appear to be the same the lever sticks out too far to use it on Eccles. The tip of the CB400 master's lever almost touches the inside of the Ural/Dnepr hand guard. As you can see in this pic of the ATC250 master (black) and the CB400 master with the bad rubber (same size & shape as on Eccles now) the ATC250 lever won't fit inside the guard

01 - New master cylinder (original lever).jpg (159.42 KiB) Viewed 1064 times

So I looked at what I had on hand and the GL500 lever I modified all those years ago was the closest I had to the geometry I need now. After a couple of hours of grinding, filing, fitting and finally buffing it fits the ATC250 master

02 - New master cylinder (modified GL500 lever).jpg (166.56 KiB) Viewed 1064 times

Images superimposed to show the change better. I won't know for sure until it is on the bike but it looks good so far

03 - Comparing levers.jpg (78.65 KiB) Viewed 1064 times

While I'm waiting for the caliper kit to arrive I need to figure out which disc (& maybe which wheel) I'll use.

[Sidecar Bob]

The caliper kit I ordered arrived, as well as the M7x1.0 bleed screws I ordered around the same time (the originals are rusty and the spares I have for Honda/Nissin calipers are M8x1.25.). I thought I had all the parts until I got a chance to start cleaning the caliper on Saturday and realized I didn't have new boots for the caliper pins. I spent a bunch of time online but decided to see if the local Suzuki dealer could get them faster so I called them yesterday morning: "Let me check. How many do you need? I have 2 of them in stock." So I picked them up yesterday.
The caliper body is soaking in mineral spirits so that the grease/dirt/old brake fluid should come off easily when I get back to it.

BTW, this is happening in between gardening and finishing up the kitchen renovation. I couldn't work on the brake parts in the garage for the last couple of weeks because I was painting the kitchen cabinet doors & drawer fronts in there. That's finished now but I still need to repair one of the kitchen windows and paint around it so I probably won't get Eccles into the garage for another week.

[Sidecar Bob]

Yesterday I finished cleaning up the Suzuki caliper. All the parts are ready for assembly

04 - Caliper ready for assembly.jpg (205.3 KiB) Viewed 671 times

After that moved Eccles from the shed to the garage. I had to hammer the caliper to free it before I rolled it out of the garage, even though I had freed it up just before I moved it to the shed. I guess that's a sign that changing to a different type of caliper is a really good idea.

[Sidecar Bob]

Old (Honda/Nissin) caliper

05 - Old caliper.jpg (176.22 KiB) Viewed 614 times

Test fitting the new (Suzuki/Tokico) one. I didn't expect its bracket to bolt up directly but the upper bolt is pretty close (there is no clearance between bracket & disc but I can modify the disc I'll actually use for that).

07 - New caliper (test fit).jpg (165.02 KiB) Viewed 614 times

Caliper removed from bracket for better access while figuring out how to connect it to the lower lug.

08 - New caliper bracket.jpg (159.25 KiB) Viewed 614 times

[Sidecar Bob]

Here are the parts I made to attach the lower mounting points. 2 of them are links, the 3rd is a washer/spacer for the upper attachment made out of the same piece of aluminum as the thinner link. I left the tab to make it easier to get it into place during assembly. This is the first time I used the little belt grinder I bought at Princess Auto last year for an actual project
Not shown is the 25mm long spacer for an M10 bolt I made on the lathe.

09 - Bracket parts.jpg (151.06 KiB) Viewed 614 times

When I put a bolt through the lug on the fork the bracket hit its head so I notched the bracket

10 - Caliper bracket modified.jpg (193.37 KiB) Viewed 614 times

Test fitting. I need to get a bolt the right length for lower lug (3/8x1-3/4) and an acorn nut for it.

11 - Bracket (test fit).jpg (160.07 KiB) Viewed 614 times

Close up. With the bolts loose there is very little movement in the direction of rotation so this should work well

12 - Bracket close up.jpg (129.66 KiB) Viewed 614 times

That's all the progress so far. I've ordered new tires (I'll replace the front one while the wheel is out to change the disc) and I'll need to borrow a friend's lathe to work on the "new" disc because mine isn't big enough.

[Sidecar Bob]

There was barely enough for the 7mm thick disc I want to use to fit between the pads. Turns out the disc the caliper was made for is only 5mm thick. So I set up the poor man's milling machine and reduced their thickness by 0.5mm
Note that this is OK for soft material but I wouldn't try machining anything hard this way.

13 - Poor man's milling machine.JPG (133.99 KiB) Viewed 604 times

Now the disc fits between the pads nicely. BTW, the friction material is still half a mm thicker than what's on a new pad for the Honda caliper.
Before & after

14 - Pads before & after milling.jpg (157.01 KiB) Viewed 604 times

I also removed the front wheel so I could remove the disc and bolt the new one on temporarily to figure out that I need a 5mm spacer. Now I need to find some 5mm aluminum stock.....

[Sidecar Bob]

The "new" (older) disc is from a '70s GT380. It has less offset than the original so it needs spacers to move it 5mm farther from the hub. I didn't have (& couldn't get) a piece of aluminum big enough to make a ring spacer but H had a piece of 3/16" (4.8mm) aluminum (close enough) big enough to make individual spacers for each of the 5 m8 bolts. So I traced around a 5/16" washer 6 times, drilled 6 holes and got busy with the hacksaw. I really need a little bandsaw :yep:
The longest 5/16 bolt I had on hand only had enough straight shank to hold 4 of them at a time so I put 4 on it, turned them, swapped in the other 2 blanks and turned them

15 - Spacers (ready to turn).jpg (192.21 KiB) Viewed 552 times

16 - Brake disc spacers.jpg (170.65 KiB) Viewed 552 times

The tires I ordered Wednesday morning were at the post office yesterday. I can't recommend Fortnine highly enough.
They are marked "Golden Boy Trail Tire SR244" so I wondered if they had sent the wrong ones but a quick Google search revealed that the name on them is some sort of Korean marketing thing and they are indeed Shinko 244s. They look pretty good so we'll see how they do in snow.

The GT380 disc is actually about a mm smaller diameter than the original (CX650E) one but it is still a bit too big for where the caliper is going to be. And the hole in the middle is a couple of mm too small to fit over the boss on the hub. My lathe can only handle 180mm diameter so I'll be visiting a friend with a bigger one in a couple of days.
I'll take the wheel with me to verify the fit on the hub so with everything else I can do for now done and the new tire in hand I removed the K270 to make that easier. I don't know what I did different when I mounted it but I didn't need to use my bead breaker to get it off.

BTW: The boss on the left side of the hub is longer than the one on the right, which will work better with the spacers so I want to flip the wheel. But the bearings are offset within the hub so I'll need different axle spacers. With any luck I'll be able to get some aluminum to turn them from but worst case I can stack some shorter steel ones I have to make up the lengths.

[Sidecar Bob]

Early experiments with the axle spacers led me to put the old ones in (with the wheel the same way around) and measure the distances between the wheel and each of the fork sliders. Turns out the wheel was offset a few mm to the right. It was probably like that since I replaced the mechanical speedometer drive with a spacer about 12 years ago.
At that point I decided it was more important for the disc to be centred in the caliper bracket than it is for the wheel to be centred between the forks precisely (as long as it isn't close enough to rub or something like that). Which meant I wouldn't know how long the spacers needed to be until after the disc was bolted to the wheel but I could make them longer on Sunday cut them to length later.

So off to visit the larger lathe on Monday and now the new disc is now a perfect fit on the wheel. And the bolts for the disc are the right length for the first time since I removed the 2nd disc when I put Eccles together 17 years ago

17 - New disc mounted.jpg (131.78 KiB) Viewed 467 times

And the disc is the perfect diameter to clear the caliper bracket while the pad sweeps just about in the middle of the remaining disc area.

18 - Pad on modified disc.jpg (146.44 KiB) Viewed 467 times

With that established I spent a couple of hours putting the wheel in & out and playing with spacers & washers until I got the disc so close to centred in the bracket as makes no difference.

[Sidecar Bob]

The next job was to figure out how to mount the speedometer magnet and sensor.
As you can see in earlier pictures the original disc has a row of slots 10mm wide inboard of where the pads grip it so it was easy to mount the 10mm dia. magnet holder in one of them. For Mr.H I drilled a hole in a disc between the carrier and where the pads grip. I expected to do the same for this one but the edge of the carrier is too close to the grip area.

An online search found a number of recommendations to simply epoxy the magnet to the disc. I wasn't entirely happy with that idea so I drilled a hole in the disc just deep enough so the face of the magnet protrudes about a mm more than the heads of the rivets.

For both previous sensor installations I drilled & tapped holes in the caliper brackets to accept the sensors. This time I decided to take a more conventional approach and use a small bracket bolted to the caliper bracket.

20 - Speedo sensor bracket.jpg (145.7 KiB) Viewed 467 times

In this pic you can see the magnet near the end of the sensor.

19 - Speedo sensor & magnet.jpg (122.11 KiB) Viewed 467 times

I gave up on trying to keep aluminum fork sliders presentable on winter bikes a long time ago. Some years ago I decided to try painting Eccles' forks with grey rust paint. It held up pretty well but a decade later it was getting pretty shabby so this was the time to deal with that.

21 - Forks sanded.jpg (168.99 KiB) Viewed 467 times

And a while later they looked like this (this time I mixed my own grey so it is a bit lighter).

22 - Forks painted.jpg (127.79 KiB) Viewed 467 times

I'll need to let the paint cure for a few days before I can put everything back together.

[Sidecar Bob]

I re-assembled Eccles' front end today

24 - Front end assembled.jpg (175.28 KiB) Viewed 386 times

The next step should have been removing the old brake system, draining it and connect the new caliper and master cylinder to the old line. While I was lifting the caliper through the fairing I felt something sharp. I bought this line when I was putting the GL500 outfit together in 2000. I guess 23 winters is a pretty good lifespan.

25 - Need new brake line.JPG (93.37 KiB) Viewed 386 times

[Sidecar Bob]

The brake line arrived Monday but it was sunny & warm out so our time was tied up clearing plants out of the veg garden that didn't survive the hard frost a couple of nights before and I spent most of Tuesday on outdoor jobs (putting things away in the yard &c) too.

I did find time to take a pic of the brake line parts, though. Note that I bought a Magnum line and Russel fittings. This is because the Magnum lines were on sale so it cost half the price of the Russell line but the Russell fittings were 2/3 the price of the Magnum ones. They are all AN-3 standard so there should not be any problem mixing brands. I also bought a slightly longer line than the old one so that I would have more routing options.

26 - New brake line.jpg (192.23 KiB) Viewed 234 times

Here's the new line installed at the caliper. The straight fitting on the old line was never a good fit against the Honda/Nissin calipers; I always had to either use an extra crush washer or 2 between the banjo and the caliper or grind a bit off of the caliper to clear the fitting or both. And even then there wasn't much room between it and the bleed screw. This 35 degree fitting is much better.
BTW, the damage to the old line was where it was zip tied tightly to the eye bolt on the fender. I figure it must have rubbed against the eye bolt every time the suspension moved.
This time I spent a lot of time experimenting with routing the line to minimize rubbing. I still zip tied it to the eye bolt so that it can't flop to the side but left the zip tie loose. Hopefully between that and the new line's plastic sheath similar damage will be avoided.

27 - New line (caliper).jpg (154.94 KiB) Viewed 234 times

And at the handlebar. I think that single zip tie will be adequate to keep it from rubbing anything but I won't know for sure until I can squeeze the brake lever and bounce the front end. And I won't be able to do that until I buy some brake fluid. I knew there was something else I needed when I was in Canadian Tire last week.
Sounds like I need to go for a ride this afternoon now that the sun is shining again

28 - New line (handlebars).jpg (153.87 KiB) Viewed 234 times

[Rat]

Maybe you explained earlier and I missed it, but why not run the line through the eye bolt ?

Gord

[Sidecar Bob]

A couple of reasons:
1) It's hard to see in the pics but that eye bolt's eye is oblong, not round. I inherited a couple of dozen of them from my Dad; I seem to recall him saying that they were packaging from something he helped un-crate where he worked.
2) A round 1/4" eye bolt's hole is about 1/2" ID, which is barely big enough for the nut on the end of the brake line to fit through without the banjo fitting so I could change it if I really wanted to. But I'd rather not have to undo the banjo from the line or the eye bolt from the fender if I need to detach the line from the fender.
I would need a minimum 17.5mm ID for the banjo to fit through. I don't think they make 1/4" eye bolts with that big an eye (would be almost 1-1/4" OD) and I really don't want to use a 5/8" eye bolt to get that big a hole

[Rat]

Thanks

Gord

[Sidecar Bob]

No problem. I had a look through the pics of Eccles I have of Eccles to see if I had one that showed it better. It looks like that eye bolt has been there with the brake line tied to it since the fall of 2012 (you'd think in a decade of pics there would be one that showed it clearly but no luck). I'll try to remember to take one the next time I'm in the garage with a camera.