Triumph Rat Motorcycle Forums banner

Street Twin - Front Brake Hydraulic Line Chafing

8K views 36 replies 11 participants last post by  J M L 
#1 ·
Giving the ST a wash and clean up after riding this weekend. I noticed the front brake hose was chafing. I'll snap a shot to explain better if no one follows me from this.

There's a thin black plastic brake line. This routes down from a banjo joint at the bottom of the steering head stem to a black rubber grommet by the left fork leg and next to the the top of the mudguard (fender for US owners).

This brake line runs round to the front of the bike in what I can best describe as an arc from the banjo down to the grommet. Its the stretch of line that has to bend (tightens and opens the arc) as the front forks compress or rise. Just after the line leaves the banjo it runs forwards between the fork gators and below a small square finned electrical box (air cooled box for generator diodes I think). Look directly below your headlight to spot the electrical box. My brake line has been catching the very bottom edge of the box under only gentle braking.

The box it catches is a cast aluminium heat sink that's bolted firmly to the bottom steering yoke (triple tee or tree for US). The brake line is slowly rubbing through where it catches regularly and there's a set of further small scapes across the line where it looks to slide along the sharp bottom of the electrical box.

Suggest all owners have a look at theirs to see if its safe. My ST has 2,000 miles on it and looks like it will be some time before it wears through. I would suggest Triumph are made aware next time the bike is with them so a shorter line or re routed line is fitted under warranty. For the mean time I will keep an eye on mine and might find a way to pull it over out of harms way with a cable tie or something.

Of some concern will be where owners have reduced the ride height of the front forks by lowering the fork clamps/yokes/triples down the fork legs. Alternatively by fitting shorter fork springs to get a lower ride height and quicker turn in. This is bound to have brought the brake line into more regular and heavier contact with the bottom of the electrical rectifier/diode finned casting.

Last ride out my front brake was shuddering under slow speed braking. Now I'm wondering if the hose being bent by the box in time with the slight dive of the fork was responsible for setting up and causing a resonance.
 
See less See more
#2 · (Edited)
Picture worth a thousand words

Here's a shot of where the brake line catches the rectifier under the headlight. Chaffing can be seen on the line near dead centre of the picture. Don't let your eye be drawn to the reflection of the flash in the glossy line finish. Look directly above that. Line strikes hard when the suspension compresses under braking or when hitting a bump.

Might be responsible for the not so great feeling from the forks I suffer at times.

Nothing here worries me enough to go running to my Triumph dealer but I will be keeping a keen eye out for any further deterioration.

I'm not sure other models in the wet twin range have the same routing of the brake line. Other single perhaps but may be not twin disc models. Might be worth a check on any versions though.

From my experience in the automotive world this would be a recall for new brake lines if found on enough vehicles. Different as these flexible lines are plastic and not the more usual rubber. More or less susceptible to chaffing? Seems we are the guinea pigs.

Has anyone else the same marks on their line from catching the rectifier? Should add my bike is stock front suspension.
 

Attachments

#3 ·
Two suggestions. First, if you're comfortable with loosening up the line at the banjo fittings then change the angle so that it doesn't hit the offending part. Of course you take a chance of slight leakage and possibly air in the line which would necessitate bleeding the system. Or, just wrap the section with a plastic sleeve until going to dealer. It is possible the line is too short, angle at fitting is off. Either way it needs to be addressed.
 
#5 ·
Comfortable loosening slightly to reposition the banjo but it won't do any good. One direction takes the loop of line higher and more prone to catch. Other tightens the loop dangerously tight but it will still catch. The fitting the banjo fits onto does not have any stops as I'm used to seeing. Means any tightening of the loop will risk the line working the banjo loose in any case.
 
#11 · (Edited)
Quote:
Originally Posted by gregoz View Post
just had a look at my T120 and theres a plastic edge protector around the rectifier
runs down both sides and bottom.

That's a very useful contribution. Thank you. Picture would be great. No such protection on my ST. For my mind says Triumph know they have an issue. Although not ideal to leave anything rubbing a brake line I might make up similar if Triumph don't have a long term and lasting safe solution.

Picture attached showing relationship of banjo, brake line and the back of the rectifier. See rectifier bolted to the front of the bottom triple or bottom yoke. See how the bends in the line are already very tight where it comes out of the ferrule of the hose end. And again where it turns to go down to the brake caliper. So tight its a wonder the banjo does not slip round as the suspension moves. At least the forces from the line are in the tightening direction. Still happy that Triumph did a great job of hiding all the modern tech like this from view. What makes the ST look so clean and pure. Just need to check their work over for peace of mind.
 

Attachments

#13 ·
wil have a good look today my T120 was made Dec/2016 any T120owners reading post
that were made earlier, can you confirm you also have edge strip this may tell us if its been added
to stop wear on line,it looks like 2 pieces, one left one right, a tab on each one that gets placed on rectifier
rectifier bolts go through them to hold in position, channel runs around edges and bottom.possible spare part you may be able to buy
if rectifier sizes are the same
 
#14 · (Edited)
... it looks like 2 pieces, one left one right, a tab on each one that gets placed on rectifier.....possible spare part you may be able to buy
if rectifier sizes are the same
Thank you once again. Found them for T120 on parts diagram - T1300059 Moulding, Regulator Rectifier, and T1300173 Moulding, Regulator Rectifier, RH. Last numbers on diagram which suggests an addition or after thought.

£30.76 ---- EACH--- :surprise:

Rectifiers appear to be the same on ST and T120. But £60 for two bits of plastic to correct a problem they know about :crying:
 

Attachments

#16 ·
Out of curiosity, I checked my Street Twin. I don't know the manufacture month, but it's a 2017 model I picked up in August, 2016, in the US. The brake hose is scuffed just where the rectifier would hit it. You can see it near the "01". I also have about 2000 miles on the bike. The scrape doesn't look like much in the picture, but rubbing a finger on it makes it very obvious.

The rectifier doesn't have plastic covers on it.

Unfortunately I have no plans to be at a dealer soon, but I think this is something that needs to be brought to their attention.

 
#18 ·
Bad design and a mediocre fix by Triumph. You could buy some stock AL and fork your own with an actual rounded end where it contacts the line. Might prolong the inevitable. The only real fix I can see us a longer brake line. Seems like a good excuse to get so.excited steel braided lines!
 
#25 ·
SB530 removal of this clip been done a long time ago



Mentioned earlier in this thread that the above SB had been done. Now found that the clip this refers to (removed on my bike some time back) is not the problem. Brake hose is rubbing in two places. The bottom of the rectifier as in my earlier picture (why I started this thread) AND also now find its rubbing in a new place on the front mudguard. Mark on mudguard is very close to where the clip would have rubbed but its the brake line catching the guard near the grommet when the suspension reaches full compression.

So my conclusion is that the loop of brake line from the banjo under the steering head to the grommet on the front mudguard is too long. Or put another way it forms slightly too larger radius to fit between rectifier at the top and mudguard at the bottom when the suspension is close to or at full compression. Hence in most owners case its likely only going to be noticed after some miles and time (perhaps out or warranty). Of course my bike highlights the problem as I often carry a pillion which means I use much more of the front forks travel than usual.
 
#22 ·
From a cooling standpoint, there's no better location for the voltage regulator/rectifier than where it is stock. I had a Ducati where it was mounted under the seat where it got no cooling air flow. It became incredibly hot on each ride. Then, one day, it melted right through its plastic mount and it was game over.
 
#24 ·
yup, under the seat might not be ideal, specially cause there is hardly any space there to begin with plus it would come with its own set of problems like wires getting chafed / cut under the seat.

i was thinking somewhere above the radiator like on the older twins. just out of curiosity, where is the rectifier placed on the new thruxtons?
 
#27 ·
This is dangerous if left long term. All bikes will be doing the same. The day someone pulls on the front brake and the line bursts through at the thin spot will be frightening. I am not willing to accept anything other than a new line and routed so that it is not being damaged. Triumph should attend to this on every bike. Full stop.
 
#28 ·
Early Bikes Only

this issue concerns only the early water cooled twins 2016 or so . the newer ones are being delivered with the plastic moulding around the rectifier as mentioned previously on this thread.

I had notified my dealer of this issue and Triumph India (completely useless most of the time) denied any knowledge of the same. don't think a fix of early models has been released by Triumph yet.
 
#30 ·
this issue concerns only the early water cooled twins 2016 or so . the newer ones are being delivered with the plastic moulding around the rectifier as mentioned previously on this thread.

I had notified my dealer of this issue and Triumph India (completely useless most of the time) denied any knowledge of the same. don't think a fix of early models has been released by Triumph yet.
My 2017 ST is affected. I also have the older style beige plastic front master cylinder, instead of the newer smoked plastic version seen on newer 2017 models. It lacks the molding on the rectifier.

So the variance is probably within early and later 2017 batches, with that smoked master cylinder being the easiest to spot visual indicator.
 
#29 · (Edited)
I'm concerned Triumph and their dealerships think SB530 has addressed this issue. And the confusion means we get told about SB530 when this further damage is brought up. Much as it was earlier in this thread.
Triumph know its happening because they have introduced that guard for later bikes.
Even if only 2016 made bikes are affected its still a lot of dangerous bikes. Hope we don't have to wait for an accident before they take some action.
 
#31 ·
from my understanding of things SB530 (clip removal) was only supposed to prevent the front fender / mudguard from being scratched. It didnt work, the front fender / Mudguard on my ST still got scratched. Newer ST's are coming with some sort of film / tape on the said area.
@Delta, so the early 2017 model ST's are also affected. we can only guess as to when Triumph became aware of this issue and when they started installing the plastic moulding around the LHS of the rectifier on the ST's.

if all the 2017 model ST's with the smoked master cylinder do have moulding around the LHS of the rectifier, it could possibly help some of the potential ST owners before they take delivery.

we be the beta bike testers.
 
#36 ·
After calling Triumph UK to report my dealers lack of interest in dealing with the outstanding safety issues with my bike, I finally got my wearing through front brake hose replaced. Fitted a much better made more flexible one introduced for the Street Cup. Made of more usual braided hose and so short it does not catch fender or rectifier. Seems the earlier fix of plastic bits put on the sharp edge of the rectifier and sticker on the mud guard to stop wear and scratching are now also deemed unsatisfactory. Brake hoses catching anything are a sure fire MOT (ministry of transport test) failure so be prepared as early bikes reach three years old.
If required I can post the part number which as far as I can see will be a complete fix for safety and later testing should anyone have to shoulder the cost themselves once the bike is out of warranty. I'm six months out but they seem to have realised their attempts to fob me off were not going to work.
 
#37 ·
I came here to post a followup, and see I won't be the first to awaken this zombie.

I finally had my bike into the dealer, and the service tech wrote up the scuffing as a warranty claim. It took a week to hear back from Triumph, and they are paying for a new brake line and plastic cover for the rectifier. Nice coincidence that it will happen at the same time as my two year service, when the brake fluid needs to be flushed; I'll only have to pay to do the rear.

The service tech was concerned that the new bikes on the floor had the plastic cover, but there was no service bulletin or anything about older bikes. He clearly hadn't seen the problem before, but also was in complete agreement with me that there is an issue.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top