Yup - that much lever deflection sure sounds like a hydraulic issue to me.
QUESTION for Gary: if the pads are glazed - can you sand them and reuse them? I would guess yes - but I have never experienced this issue myself.
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Poor braking from 11mm MC
- Thread starter Sci85
- Start date
Yup - that much lever deflection sure sounds like a hydraulic issue to me.
QUESTION for Gary: if the pads are glazed - can you sand them and reuse them? I would guess yes - but I have never experienced this issue myself.
Yes, take a good look at the rotor also
Royboy
many roads, little time
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For several years now I've been using the Brembo 11mm M/C's and stock calipers on both the 650's and my SR500. Like Grizld I find that that M/C coupled with Vesrah pads and stainless one piece lines gives the best braking and best lever feel. I've considered going to Brembo calipers but don't really see the need. I'm guessing that you are fighting air in the line.
roy
roy
Well Griz is our winner! I put in a bolt and pumped her up. Once the air was out of the MC, lever was rock hard. So I inspected the rest of the setup and I think I over tightened where the line connects with the end connector and it was letting air in. This was a custom line and I just got over zealous on it. I may need to order a new line now but I'm pretty sure that is the culprit.
Thanks again guys.
Hi Sci,
another thing a person could get over-zealous with is the brake bleed nipple.
My son had an issue with his XS650 front brakes (We'd gone t'other way, kept the stock M/C and added the leftside caliper & disk)
Turned out he'd tightened the caliper bleed nipples so hard that their little pointy noses had warped out of shape.
Shoulda warned him about the hazards of getting medieval when using a long-series box end wrench.
When working on brake lines, its the copper washer that does the sealing. Very little torque is needed to achieve a leak tight seal. Use a new copper washer(s), so it has no surface damage. I use an "inch/pound" torque wrench, and use only 96 in/lbs of torque.
Sometimes less is more.
Can't claim to have identified the source of trouble, Sci; you just tested the MC for function, and it passed. If the banjo wasn't sealed you'd have been leaking fluid there. Try this. Go to the grocery store and buy a turkey basting syringe. Remove the needle, attach a piece of clear hose, hook up to the bleed nipple on the caliper, open same, and pull back on the plunger till nearly full, watching for bubbles. Close the bleed valve, and if you got bubbles, check fluid level in the MC, empty the syringe, and repeat. If you still see bubbles after half a dozen repetitions, you have an air leak at the caliper seal.
On my dirty pads, mostly just road grime I sand blasted them. Looked like new and work fine. Same on the rotors. The bit of roughness like by the sand really improves grip, for awhile anyway. After awhile the braking action polish's thing up.
Leo
Leo
Well after trying out Griz's trick, I put it all back together and spent a good hour bleeding the system and sure enough, it feels a whole lot better now. I raised the caliper above the MC this time and bled it that way. Then, I put the caIiper below the MC and tapped on the line quite a bit which seemed to work well as I saw tiny bubbles rise up into the MC. Thanks all for the help. Much appreciated!
There is a very simple way to prevent all of this "air trapped in the brake line", and the lever is too soft story, that seems to happen a lot with these bikes.
Why spend time bleeding air, when the best way is to start with the brake line full of fluid, so there is no air to bleed.
Do not install the empty new brake line on the bike. I fill the caliper first using a syringe. Now with the new empty brake line on the bench, form a U shape, and fill the line with brake fluid using a syringe. Fill the U from one end, and when the fluid comes out the other end, the line is full. Keep the line in the U shape as you connect one end to the caliper. Once connected, raise up the full brake line and connect it to the master cylinder. Fill the master cylinder and you're done. The bleeding becomes a thing of the past, as there is no air to bleed.
Why spend time bleeding air, when the best way is to start with the brake line full of fluid, so there is no air to bleed.
Do not install the empty new brake line on the bike. I fill the caliper first using a syringe. Now with the new empty brake line on the bench, form a U shape, and fill the line with brake fluid using a syringe. Fill the U from one end, and when the fluid comes out the other end, the line is full. Keep the line in the U shape as you connect one end to the caliper. Once connected, raise up the full brake line and connect it to the master cylinder. Fill the master cylinder and you're done. The bleeding becomes a thing of the past, as there is no air to bleed.
This thread reminds me that I miss hearing from @retiredgentleman!
On a stock XS650SH I changed the MC from 14mm to 12.7mm from a Virago 400. This gave a nice improved feel to the brakes without being too excessive.
Today's challenge is:
I have a Virago with twin front disks and each caliper has 2 opposed 38mm pistons. The stock MC is 16mm. I have been considering changing to a 14mm MC???
The Ratios for total caliper piston area divided by that of the MC are:
https://www.vintagebrake.com/mastercylinder.htm
Does anyone have an ideal as to the recommended Ratio for twin disks with a total of 4 opposed pistons?
Thank you for any feedback.
Today's challenge is:
I have a Virago with twin front disks and each caliper has 2 opposed 38mm pistons. The stock MC is 16mm. I have been considering changing to a 14mm MC???
The Ratios for total caliper piston area divided by that of the MC are:
- MC = 16mm Ratio = 22.6
- MC = 14mm Ratio = 29.5
https://www.vintagebrake.com/mastercylinder.htm
Does anyone have an ideal as to the recommended Ratio for twin disks with a total of 4 opposed pistons?
Thank you for any feedback.
I would like to know how you order brake lines with the Banjo’s in different planes? I have been put off ordering from Banggood because there is no stipulation for this choice.
Well, according to that Vintage Brake chart and recommendations, 15 mm would be near ideal MC for 4 x 38 mm pistons, while 14 mm may just be a bit small. However, caliper rigidity and hose expansion will also influence brake feel. Maybe there are master cylinders out there with a 9/16" bore? They would be slightly larger than 14 mm.
Rasputin, unfortunately you can't stipulate the plane on the line ends from Banggood. They are what they are. Pretty much all these low cost Chinese lines I've run across have the ends in the same plane. This works well for a MC that attaches it's line on the front .....
Fortunately for us, most of the smaller MCs we switch to do. You need a line with it's ends at 90° to one another for a MC that attaches the line to it's end, like the stock 650 units do .....
Fortunately for us, most of the smaller MCs we switch to do. You need a line with it's ends at 90° to one another for a MC that attaches the line to it's end, like the stock 650 units do .....
Expecting quick delivery from China could result in a surprise delay right now.
This is true in my particular case.
I have checked the tracking which is good to see but there has been significant delay.
I now expect to have Chinese brake lines in hand in mid May.
More than a month later than originally expected.
This is true in my particular case.
I have checked the tracking which is good to see but there has been significant delay.
I now expect to have Chinese brake lines in hand in mid May.
More than a month later than originally expected.
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ArcticXS, thank you for that info. I suspected 14mm might be too big a jump. I may just try it if I am locked up for another 2 weeks at home. Maybe it will work for my calipers, rotor and brakelines - Will give me a bit of fun!
Today: So off came the 16mm and on went the 14mm MC. Went on a 2 mile stop start ride and the brakes were nice. Not at all spongy or wooden and definitely not locking up easily. When I got home I touched the disks, right was very hot and the left was warm. I have a suspicion the right piston on the left caliper is a bit tight. Does this sound familiar to anyone? With at least two more weeks of lockdown I am tempted to strip the caliper down. Does anyone remember the name of that little rubber boot that protects the MC piston from the weather?
Note: I do have new stainless brake lines fitted.
Note: I do have new stainless brake lines fitted.
I have now dismantled the calipers. There was a seized piston on the left side so this explains why the left rotor was only warm. Will now order seals and finish the job later this week. I may find the 14mm caliper is not so good so will change back to 16mm and then decide what the brakes are like post new seals and polished pistons. Lucky for me the bike already has stainless steel pistons.
Edit: All parts ordered and should be here Thurs or Friday. I plain to use Castrol Red Rubber Grease to lube the seals and pistons on reassembly, but first there is some serious cleaning to do.
Edit: All parts ordered and should be here Thurs or Friday. I plain to use Castrol Red Rubber Grease to lube the seals and pistons on reassembly, but first there is some serious cleaning to do.
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