Rear disc brake ABS LBS TCS

[lonerider41life]

I have a problem with the rear brake on my motorcycle. It gets excessively hot, I think. The brake disc on my rear wheel is worn, beyond the limit and needs replacement. Is there any equivalent model from other honda motorcycles, especially st1300. Mine is ST1100 model 1998 abs tcs lbs. What are the dimensions of the disc, to search for replacement?

 

[Upt' North]

EBC make a rear disc for the 1100A.
I'm sure you'll service the rest to ensure it doesn't get so hot again. If indeed it did.
Upt'North.

 

[kiltman]

I ended up getting a new one off of eBay, it’s from China. Works well, though I did have to take it to a machine shop to counter sink the mounting holes. Not really necessary if you don’t have electronic cruise control. (I mount magnets on the bolt heads for the speed sensor of my cruise control)

 

[lonerider41life]

The braking system has not been completely dismantled. The calipers were removed from the grips, the brake pads were removed, the parts of the calipers were separated (the part with pistons versus the one without jaws), cleaned, replaced with petroleum jelly. The pistons work freely, they easily come out of the cylinders when the lever and pedal are pressed and they retract easily when they are released. The pressure hoses were not removed, but the brake fluid in the system was completely replaced, according to the procedure in the manual.

 

[STRider]

The braking system has not been completely dismantled. The calipers were removed from the grips, the brake pads were removed, the parts of the calipers were separated (the part with pistons versus the one without jaws), cleaned, replaced with petroleum jelly. The pistons work freely, they easily come out of the cylinders when the lever and pedal are pressed and they retract easily when they are released. The pressure hoses were not removed, but the brake fluid in the system was completely replaced, according to the procedure in the manual.

I would be concerned that you used petroleum jelly in an application that could allow it to contaminate the brake fluid. Every procedure I've ever seen about servicing hydraulic brake systems is to use brake fluid for lubrication during assembly. Never anything else.

"Petroleum jelly (also called petrolatum) is a mixture of mineral oils and waxes, which form a semisolid jelly-like substance."

https://en.wikipedia.org/wiki/Petroleum_jelly

You do not want this anywhere near your braking system.

 

[lonerider41life]

Temperature grease aplied to bolts that keeps both parts of brake calipers togather, not on calipers pistons. I don't know how to say, google translate named petroleum jelly

 

[SMSW]

Is that scoring on your brake disk or just discoloration? If scoring, that is severe wear that was caused by sticking brake pads or piston(s). But it sounds like you would have corrected the cause by overhauling your calipers.

Regarding the lube you used, if it was a brake compatible lubricant, I'd not worry. As @STRider said, either brake fluid or a silicone paste for brakes are the only lubricants that I know are safe to use. Your 'temperature grease' was probably a thread locking type substance - we are now getting into linguistics discussions.

There have been discussions on what brake pads to use. It is my understanding that EBC pads are more aggressive and can cause excessive disk wear. Most of the guys here prefer Honda pads. You can go to the blue band atop this page, click on the search box, enter brake pads and read some threads about the pads. Or, click on Forums atop this page, scroll down to ST Forums, then ST 1100 Related, click on ST 1100-Brakes and read some of those threads.

 

[Tom P]

The disc new is 6.5 mm as it says there in your photo. If you don't have a calipers Harbor freight has one plastic for a couple bucks. It works great. I think the limit for wear is around 5 mm. Quick and easy way to check. A new 1300 is 7 mm and I replaced mine with scout 190,000 miles on it.
P.S bought it, OEM, off ebay from a salvage bike company that had great reviews. He mic it out a 7 mm and sold it to me for 50.00 w/ shipping

 

[Andrew Shadow]

The 6.5 mm that is visible in that photo is the minimum thickness at which replacement is recommended by Honda for an ST1100 equipped with LBS brakes.
New rear brake discs are somewhere between 7.3 and 7.7 mm thick.

 

[lonerider41life]

As I said before, the braking system was not fully disassembled, the calipers were removed from the wheels and the pistons were cleaned without being removed from them, only pushed outwards with the help of the brake lever or pedal (all three at all calipers), up to the limit of full output, without falling out. I didn't remove any hoses. After cleaning, they were pushed, at the same time, to their place inside. Along with this cleaning operation, I also replaced the brake fluid from the entire installation (again), by pumping and filling successively in the tanks, according to the method described in the brake bleeding section (in the manual), using about 1.5 liters of fluid, until the fluid came out as clean to the aerator, like the one put in the tanks.
The temperature grease, which I used to grease the sliding parts of the calipers, marked in red in the attached image, is Mannol 8025 brake grease (I didn't know exactly than, because I received it a small amount in a box, from a friend).
The brake disc on the rear wheel is scoring and discolorated (blue), indeed, and measures only between 5.5mm and 5.9mm thick, so far below the limit of wear.
Just as I said before, when the brake lever or pedal is actuated, the pistons actuate the pads on the disc, and when the levers are released, they retract slightly into the caliper, releasing the pressure applied to the pads.
Looking for rear brake discs, for the 1998 ST1100AW model, I found them in three places, with quite significant differences in price and delivery time. The most expensive disk is from MTX, stainless steel, thickness 7.8mm (124.99 GBP + 32.66GBP shipping + 31.71GBP custom duties, delivery 12-14 days) and I found it here: https://www.ebay.com/itm/265222836414?hash=item3dc08350be:g:2lQAAOSwX95g5r8j&amdata=enc:AQAHAAAA8EUVcbQaNjAHSKYzB2zy++7uhoMZsruaASZNXC9Ctt+lWgZFZ/dPBW42r66L7I4p+NwxSauQOvL99t+Y1XOiOEkn61zPMzqWIuzJLcQuyUBQThC6/ELrxtMKUZXNv5y1ZdZs3nVyCEf6Jl3AvJN3KzhHQRPqTHq+0KcUW1ylKDV2ECmFqWUPRVTmnPBiBxw3HTPkar8Ud2+SpSHeQBsPTNDke4wzQHrxpZcOQ7ZK2msU8OHz0ysaiowarlGQzo2gkMf40oGAt503pjumFJewTnTYXaiZ58HbsTXD0mT3Sqfq8vjJN1fRfI/FcI6Xpr6jdQ==|tkp:BFBMuqDP9thh
The second found on aliexpress, BIKINGBOY, stainless steel, thickness 7.8mm, a bit cheaper (102.24GBP + 21.79GBP, long time delivery between 30-45 days): https://www.aliexpress.com/item/1005003954012844.html?spm=a2g0o.productlist.main.21.d9a952b09wNJAC&algo_pvid=a62e1cdc-2e84-48f8-a7f3-ddfb0260cb22&algo_exp_id=a62e1cdc-2e84-48f8-a7f3-ddfb0260cb22-10&pdp_ext_f={"sku_id":"12000027556294692"}&pdp_npi=3@dis!RON!736.47!559.74!!!!!@21227d8316783832335797406d0705!12000027556294692!sea!RO!0&curPageLogUid=p8H0zXRNjBDs
The third and cheapest is from Niche Industries (59.95 USD + approx. 40 USD shipping, delivery 15-20 days). I haven't heard of them, I don't know what quality they produce, the disk seems to be made of cast iron and thickness 7mm, but if you have used components from them, any advice is welcome. It is this one: https://nicheindustries.com/products/niche-519-crt2576r?_pos=1&_sid=3c67ac959&_ss=r
The disc from EBC is even more expensive than these three listed, but in the last resort, it can be considered. They currently have none in stock.
What would be your recommendations?
Thank you.

 

[Uncle Phil]

You have to do what you have to do, but I always try to stay with the OEM stuff on brakes.
So if you can source a good condition OEM disc I would go with a 'known' quantity and quality.
But I do understand in your part of the world that could be difficult.

 

[kiltman]

Here’s the link to the one I bought of eBay
Rear brake rotor
I have put on 10 k kms without any issues

 

[Jim Van]

I have no idea how much shipping would be to Romania but I have a new EBC rear ABS brake disc for sale - check out the For Sale section in this Forum. If you are intersted, send me a pm with your address there and I'll get a quote on the shipping cost to Romania for you. I could give you a little cost adjustment to help with the shipping.

BTW, I use clear silicone dielectric grease to lubricate the seal grooves on my calipers to prevent that "white" colored corrosion from forming and causing the pistons to get sticky and not retract properly when the brake pedal is released. It's inert and won't contaminate the brake fluid as petroleum jelly will. I have been using silicone dielectric grease like this for years without any ill effects.

 

[Yohan]

The silicone grease mention reminds of when My Honda CBX550 would get a slow air leak with new tyres .I tracked the leak down to the inflation plug and some alloy corrosion .A quick polish and some silicone grease cured that sneaky little leak .

 

[lonerider41life]

Back to the brakes.
I bought a new EBC MD1135 rear disk, which I found with difficulty here locally, and a set of pads. I mounted them but, likewise, the brake remains slightly tight on the disc, the wheel does not spin freely. What I noticed: if I leave the motorcycle from today to tomorrow, the next day the wheel turns more easily than the previous day after use, untill I use the pedal brake.
What have I done. I dismantled all the calipers from the fastening system of each one (without removing the hoses), pulled the mounting bracket off the calipers, cleaned and greased up the two sliders for all calipers, front and rear. I pushed all the pistons out, until I almost took them out, I cleaned them with some TRW Brake Cleaner and a toothbrush. They remained clean as a mirror. The pistons work freely and can be pushed back by hand (fingers). When the lever/pedal are pressed they come out, when the levers are released they all retract easily and the calipers slide easily on the two sliders. I also cleaned and greased all the moving elements (bushings, bearings, link arm) from the front calipers. SMC seems to work. Mounted them all, filling/bleeding again entire brake system with approximately half a liter of brake fluid. The liquid that comes out through the vents is as clean as that from the bottle, no air bubbles.
When I went out for a tour of about 40 km, free road and through the town, on the way back I checked the discs and calipers. If the front ones were cold or very slightly heated, the back one was quite warm to the touch, I would estimate about 60-70 °C, maybe more.
Since I'm afraid to ride with it like this again, I would still like to know if this heating of the rear brake is somewhat normal or is excessive. When the motorcycle is on central stand, with the engine stopped and the rear wheel is turned by hand, friction between the pads and the disc is heard.

 

[jfheath]

It is possible that the problem lies with the mechanism behind the grey cover on the left hand fork leg.


This mechanism is a linkage which is supposed to move so that when the front brake is applied, it pushes the piston of that grey master cylinder upwards, and this applie the rear brake. Its is called the Secondary Master Cylinder (SMC). On the ST1300 this device is different, witht he open end facing upwards - and it causes a lot of problems. The design on your ST1100 is much better in this respect. But if it cannot move, it cannot release the rear brake after it has been applied.



It is hidden out of site and it is possible that this mechanism has seized and is not moving. When working you should be able to push the plunger by hand and the back wheel locks. When you release the plunger the back wheel is free to rotate.

Take the shroud off. Take photos of how it is fitted together and then remove the bolts. Those three holes - two of them have needle roller bearings in them. Make sure that you know which hole fits where. I cannot help you if you take it apart and cannot work out how to put it back together ! Someone else may be able to. There is no need to disconnect the brake hoses, but be careful to support the mechanism when you slacken the bolts. You don't want to put any weight on the hoses. Check the bearings, clean up the plates. Make sure that the parts that should move, do move freely. Re-assemble.

It is also possible that the SMC itself is not moving properly. But the seized plates and bearings are well worth looking at first. Especially since it only takes a bit of time and grease to inspect and and to get it moving properly again.