I have to put out a little warning and my experience with yambits parts :negative:
The last days i have several times experienced too lose all brakingpower on front calipers both sides and the brake lever travels all way into handlebar.
It is an unpleasant feeling .The strange thing is the brakes works just fine with a firm lever most of the time.It is not like i have to pump the lever
to get it to work it just sometimes just get completely lose with no resistance and no frontbrakes.I was thinking since i done a little vertical riding the last days maybe some air had got trapped or something ,but my brakes has never got damaged from it before ,so first i bleed the brakes ,but just some tiny bubbles was coming out.I took a ride and the same happend a few times lost all brakepower in front from time to time but most of the time brake worked perfectly.
Then replaced the brakefluid and bleed the brakes one more time and checked that the vent hole in reservoir was not clogged.Took another ride and Same shit happened god brakes most of time but suddenly no brakes at all :shok:.I discovered that
it was happening mostly if i had not operated the lever for a while and slowly pulling on the lever.
I then checked for any leaks at the caliperpistons and bleedscrews and at the antidives and at the T split joint behind the horn and at all the banjo connections
no leaks was found. and the went hole in the reservoir was not clogged.Also checked the athmosphere hole in the fillecap on master reservoir lid. with bike parked and with the lever pulled into handlebar i checked the brakepads with my fingers and they could be wiggeled as they should when no brake are aplied It was a mystery to me since i have been working on bikes since i was a kid and never experienced anything like this.
Then i remebered that last winter i replaced the mastercylinder piston with a rep set bought from yambits uk.I did this just as a maintainece since i also
replaced the master piston rep set on the clutchmaster.When inspected the mastercylinder bore on brakemaster it looked like new no pittings or scorings
so i just mounted the rep set bought from yambits uk. The brakes has worked with no problems the hole summer ,but a few days ago i started to lose all brakepower .
Today i did another try to fix it by losening the 14mm banjobolt on the master with a rag wrapped around it to see if any air was trapped in there,but the same happened when took a little testride .I then tried to get hold of a new master rep kit but it had to be ordered and then i cant ride for many days.I then searched in my spare bikeparts stuff and found a bag with the old used
brakemaster rep set that was replaced last winter.
I rode up to a place i usually do some work on the bike and pulled out the yambits brakemasterkit that was installed last winter and mounted the old brakemasterpistonkit .I first inspected the new yambits kit that was sitting in the cylinderbore but it looked fine only thing i notised was that the cylbore where it sits was very black like the rubber that is fitted on the brakemasterpiston had smeared onto the bore. I cleaned the cylbore up a little and then mounted the old kit i took out last winter.
I did not even need to bleed the system only a little wiggeling on the brakelever to get the air out
And yes you guessed right brakes now works perfect again and i have rode for several hours today with no problem.
I found a picture of the parts i bought from yambits uk last winter and will post it here so you dont buy that shit.
Old Rider,
I am not sure I understand all that you had happening there, but it sounds to me like you were sold some defective parts. You may need a new master cylinder there. I hate to say this, but some unscrupulous makers are producing bad merchandise, and labeling it with a reliable brand name. Sellers may or may not know about the fraud, as they pass it on to you. I can only say, do not look for the lowest prices on important parts, such as brakes, hoses, and critical fasteners. Use reputable, well-known sources for these parts.
RPM (owner of this site) has bleeder banjo bolts, which can bleed air easily and cleanly from the vertical hoses at the clutch and front brake master cylinders. Note: Always use new hydraulic washers when changing banjo bolts, to avoid leaks.
Quote from: red on August 25, 2022, 01:22:36 PM
Old Rider,
I am not sure I understand all that you had happening there, but it sounds to me like you were sold some defective parts. You may need a new master cylinder there. I hate to say this, but some unscrupulous makers are producing bad merchandise, and labeling it with a reliable brand name. Sellers may or may not know about the fraud, as they pass it on to you. I can only say, do not look for the lowest prices on important parts, such as brakes, hoses, and critical fasteners. Use reputable, well-known sources for these parts.
RPM (owner of this site) has bleeder banjo bolts, which can bleed air easily and cleanly from the vertical hoses at the clutch and front brake master cylinders. Note: Always use new hydraulic washers when changing banjo bolts, to avoid leaks.
Hi Red ! Thanks for your interest in this post i know im not so god at explaining about what was going on when i lost all brakepower but i had no brakes at all on frontwheel several times during last days.Then inbeetween the brakes worked normally.
I found out that the cause of sudden brakefailure was that i had installed a brakemaster cylinder rep-kit i ordered from yambits uk and want to warn other riders that that might
have the yambits brakemaster repkit installed or thinking of buying one.
When i installed the brakemaster from yambits last winter i first inspected the cylinderbore in the brakemaster and it looked like new with no pittings or scoring so i just installed the
yambits repkit .I also instaled a repkit in the clutchmaster cylinder ,but the bore in the clutchmaster had some pittings and had to be honed i then used a tourmax repkit.I made a writeup on that here : https://fjowners.com/index.php?topic=20077.0 (the clutchmaster and slave is still working fine i used tourmax repkits on those parts)
When i tried to order a front brakemaster repkit last winter i did not find any tourmax repkit (not on RPM website either) ,but then i found the yambits uk website and that they had a frontmaster repkit .I have no experience with the quality on yambits parts ,but thaught since it was such a important safety part it must be okay. The yambits brakemaster repkit has been working
fine in six mounths ,but as i said earlier it suddenly in the last days has failed and left me with no brakes at all in the frontwheel several times.
So the bottom line is buy a original or tourmax brakemaster cylinder rep kit if planning to do some maintanence on the brakes.I will NEVER buy anything marked yambits again atleast
anything they have with rubber.Seems that the rubber that is used is very bad china quality
Just confirming, this kit?
http://rpmracingca.com/proddetail.asp?prod=M%2FC%3AFRTBRKRBKIT (http://rpmracingca.com/proddetail.asp?prod=M%2FC%3AFRTBRKRBKIT)
We sell a ton every year and I don't ever recall an issue reported.
Glad you found the issue and you were not injured as a result.
Randy - RPM
So the rubber seal failed?
The greasy residue in the bore sounds like the rubber deteriorated from contact with the brake fluid.
I wonder what would happen if you put the rubber seal in a sealed jar of brake fluid for a few weeks.
Rolf, what did you lubricate the seal with when you assembled it?
Man you gotta love the RPM crew. It is great to have them as a parts source for our bikes. Thanks, guys!
I have their Oil Filter Spin-On Adapter on my 1985, so I can use ordinary automotive-type oil filters instead of the messy paper-cartridge Yamaha oil filters.
It is a great accessory, and easy to install. Just be sure to use oil filters with anti-drain valves in them. The plain filters will drain out every time you turn off the engine.
Quote from: racerrad8 on August 26, 2022, 07:44:56 AM
Just confirming, this kit?
http://rpmracingca.com/proddetail.asp?prod=M%2FC%3AFRTBRKRBKIT (http://rpmracingca.com/proddetail.asp?prod=M%2FC%3AFRTBRKRBKIT)
We sell a ton every year and I don't ever recall an issue reported.
Glad you found the issue and you were not injured as a result.
Randy - RPM
Hello Randy it is strange i did not find that kit when i searched your store last time. That is not the same kit as yamabits sell i can see that by comparing them on picktures.
I know RPM only deal with high quality parts and will order it from you this winter.
Quote from: Pat Conlon on August 26, 2022, 08:24:51 AM
So the rubber seal failed?
The greasy residue in the bore sounds like the rubber deteriorated from contact with the brake fluid.
I wonder what would happen if you put the rubber seal in a sealed jar of brake fluid for a few weeks.
Phather Pat i think you are right .I used the kit since march and it has worked with no problems until the last days it failed to make pressure and the brakes did not work
from time to time not a good feeling =).Maybe the rubberseals just has worn out but in six months ? or the rubber like you say deteriorating from the brakefluid .
Here is what brakefluid i use never had problem with it damaging seals
Quote from: ribbert on August 26, 2022, 08:38:12 AM
Rolf, what did you lubricate the seal with when you assembled it?
Ribbert : the yambits kit did not included any lubricants so i think i used only brakefluid or i maybe used the pink grease that was included in the Tourmax clutchmasterkit dont
remember.But one thing i notised when i had a look at the failed yambits kit now is that one of the seal is very loose and is easy to rotate on the masterbrake piston i dont think
it is suposed to do that ?
Quote from: red on August 26, 2022, 08:39:43 AM
Man you gotta love the RPM crew. It is great to have them as a parts source for our bikes. Thanks, guys!
I have their Oil Filter Spin-On Adapter on my 1985, so I can use ordinary automotive-type oil filters instead of the messy paper-cartridge Yamaha oil filters.
It is a great accessory, and easy to install. Just be sure to use oil filters with anti-drain valves in them. The plain filters will drain out every time you turn off the engine.
Red : That is absolutly true i only had positive experiences with RPM they have top quality parts and ship fast .And Robert and Randy offer top service ! :good2:
dot 5.1 is also compatible with dot 3 and dot 4. Since these bikes used dot 3 I would think the seals used in repop kits would sustain such fluids.
Rolf, whatever the reason, there appears to be some sort of contamination going on. The gel like sludge and the degradation of the seals are both consistent with fluid incompatibility. I know you showed a photo of the fluid you used (5.1) but is there any possibility that Dot 5 brake fluid played any part in this?
There are plenty of chemicals used in the garage that will turn brake seals soft, even residue from parts washing in the wrong solvent can damage them. I can feel those seals just looking at them.
As for the piston damage, I thought the brake lever had a much bigger contact area (although it's a long time since I've seen one)
The nature of the failure is most unusual.
Noel
Haha, your photos, description and dialogue boxes have got to be the best detailed problem ever!
Quote from: RPM - Robert on August 27, 2022, 05:52:51 PM
dot 5.1 is also compatible with dot 3 and dot 4. Since these bikes used dot 3 I would think the seals used in repop kits would sustain such fluids.
I agree if the seals not made of some super bad quality.
Quote from: ribbert on August 28, 2022, 09:31:31 AM
Rolf, whatever the reason, there appears to be some sort of contamination going on. The gel like sludge and the degradation of the seals are both consistent with fluid incompatibility. I know you showed a photo of the fluid you used (5.1) but is there any possibility that Dot 5 brake fluid played any part in this?
There are plenty of chemicals used in the garage that will turn brake seals soft, even residue from parts washing in the wrong solvent can damage them. I can feel those seals just looking at them.
As for the piston damage, I thought the brake lever had a much bigger contact area (although it's a long time since I've seen one)
The nature of the failure is most unusual.
Noel
Haha, your photos, description and dialogue boxes have got to be the best detailed problem ever!
Noel : im sure i used the yamalube dot5.1 i found some picks from last winter and you can see the adjuster screw contact area it is rounded .
I like details and here are some more detailed photos i found from when i installed the yambits brakemaster rebuild kit last winter :smile:
This might be a dumb question, but why not use the OEM repair kit? They are still available from Yamaha. I did my master this spring with it.
(http://albums.indyblue.org/main.php?cmd=imageorig&var1=mc_repair_kit.jpg)
Hello Indyblue
I bought it from the yambits UK because I had just discovered the website and bought some other parts from them .They also had the rubber piece for the clutch line
In stock and then I found they had the front brake master rebuildset too, so I bought that too .It was nothing wrong with my front brakes I just replaced the set for
Maintenance Purpose since I was also rebuilding the cluthmaster that winter
I know I can get it at my local Yamaha dealer, but when buying from them i have to come to the store and pay and order the part then wait about 3-4 weeks if
the part is stored in Netherlands ,but if the part is in yamahas storage in Japan it takes long time before it is in Norway
I also searched the RPM site for the front brakemasterkit, but i could not find it then.Anyway with the new import laws here in Norway it has now got very
expensive to buy something from e bay or overseas.
So i just bought it from yambits uk since i found it there and was thinking it had to be okay quality since it is a very important safety part.
after i found out that the set has failed and the other rubberparts got rotten and brittle after just six months of use i will not buy from the again.
Quote from: indyblue on September 06, 2022, 08:51:56 PM
This might be a dumb question, but why not use the OEM repair kit? They are still available from Yamaha. I did my master this spring with it.
http://albums.indyblue.org/main.php?cmd=imageorig&var1=mc_repair_kit.jpg (http://albums.indyblue.org/main.php?cmd=imageorig&var1=mc_repair_kit.jpg)
Yeah, I would recommend OEM factory parts for critical (vital) systems like brakes. Not the cheapest, sure, but brakes are not the place to be pinching pennies, or even bux.
Obviously, your life may depend on good brakes.
Quote from: Old Rider on September 07, 2022, 10:16:58 AM
Hello Indyblue
I bought it from the yambits UK because I had just discovered the website and bought some other parts from them .They also had the rubber piece for the clutch line
In stock and then I found they had the front brake master rebuildset too, so I bought that too .It was nothing wrong with my front brakes I just replaced the set for
Maintenance Purpose since I was also rebuilding the cluthmaster that winter
I know I can get it at my local Yamaha dealer, but when buying from them i have to come to the store and pay and order the part then wait about 3-4 weeks if
the part is stored in Netherlands ,but if the part is in yamahas storage in Japan it takes long time before it is in Norway
I also searched the RPM site for the front brakemasterkit, but i could not find it then.Anyway with the new import laws here in Norway it has now got very
expensive to buy something from e bay or overseas.
So i just bought it from yambits uk since i found it there and was thinking it had to be okay quality since it is a very important safety part.
after i found out that the set has failed and the other rubberparts got rotten and brittle after just six months of use i will not buy from the again.
I didn't realize how tough it might be to get the OEM parts there. Us yanks are sorta spoiled that way.
It takes 3-6 weeks if it needs to come from Japan here too, though most things are kept stocked somewhere in the US. I order from partshark and they ship directly to my dealer parts dept., then I don't have pay any shipping I just pick them up when I get the email they're in.
Quote from: red on September 07, 2022, 10:19:04 AM
Quote from: indyblue on September 06, 2022, 08:51:56 PM
This might be a dumb question, but why not use the OEM repair kit? They are still available from Yamaha. I did my master this spring with it.
http://albums.indyblue.org/main.php?cmd=imageorig&var1=mc_repair_kit.jpg (http://albums.indyblue.org/main.php?cmd=imageorig&var1=mc_repair_kit.jpg)
Yeah, I would recommend OEM factory parts for critical (vital) systems like brakes. Not the cheapest, sure, but brakes are not the place to be pinching pennies, or even bux.
Obviously, your life may depend on good brakes.
Agreed. However, in this case if it was a choice of getting back on the road now vs. waiting for OEM and running out the rest of the riding season it might be worth a try.
Here's my 2 cents, for what it's worth....
Always use OEM replacement seals and rubber parts if they are available. I used aftermarket fork seals (supposed to be superior) on my track bike once. It was just before a 2 day track school that cost 2 grand. Lo and behold my bike failed tech inspection when the forks puked oil the first morning! The good news is I at least got the chance to rent a bike. The bad news is I was so uncomfortable on it that I high-sided it to the moon...Another 2 grand to fix it! An expensive lesson. :Facepalm: