Front wheel noise

[ssevy]

Hi guys,
I'm in the middle of my cross country ride, currently in Flagstaff AZ. At the end of my ride yesterday, I noticed a cyclical sound from the front end, and when I put it on the center stand and spun the front tire, everything turned fine.
Today at the end of my ride I noticed the same sound again. My concern is that I have never dealt with a wheel bearing issue, and wondered if someone can tell me about those symptoms and how soon they need to be addressed?
I have been running some slab to make up days I lost due to snow, so that wheel


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[ssevy]

Has been spinning at 75 mph for long hours.
Any feedback is appreciated!


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[Nick Calne]

It could also be your speedo drive. Perhaps pop the wheel off inspect all including bearings. If nothing is apparently wrong then some more grease all round and take it from there.

[Lee337]

Bearings usually make a rumbling sound. With the wheel off the ground you might be able to feel sideways movement. grab the top & bottom of the wheel and you should be able to feel some movement when rocking it side to side if the wheel bearings are on their way out. If there is any lateral movement, change the bearings - you really don't want one of them failing while you're riding

It sounds more like the speedo drive, or possibly brakes.

[Sin_Tiger]

It's possible that a bearing/s has gotten worn to the stage that, although not bad enough to rumble, has just enough clearance that it's developing a harmonic vibration that is evident when several factors such as speed, temperature, balance, tyre wear pattern, wheel spoke tension, road surface, weight / luggage distribution, rear preload and others are in alignment. If you can change it by altering one or more influences such as speed, tyre pressure, even riding with the bike at a slight angle to disrupt that harmonic, then that would suggest this is what is happening. Although I've seen similar effects on all sorts of rotating machinery, I've only ever come across this in similar prolonged higher speeds on highways on the front when the tyre blocks started cupping as they do, and managed to alleviate it enough to get to my destination in a safe manner. I'm not suggesting this is the case with your situation, more as an example of how altering one factor can disrupt the cumulative effect.

If I were in a similar situation with a longer ride ahead, I'd be tempted to get into a bike shop for a change of bearings, check the rim / spokes, perhaps even turn the tyre around the rim and rebalance it. I know it's time and expense but at the very least you could eliminate many of the factors without major mechanical surgery and give you confidence in the front end when it needs to perform. If it is still evident, then it might be a "tail wagging the dog" situation and you need to look at the back end. I'm guessing on this trip you'll be even more loaded up than usual for a camp trip.

[Nick Calne]

Elective and preventative mechanical surgery is always better than mandated corrective medical surgery.

[ssevy]

Thanks gentlemen. I did check the wheel for sideplay and the timing of the cyclical sound would make me think brake pad. In preparation for this trip I installed new pads, and while the calipers were out, I went ahead and put new seal kits in all of them and polished the pistons. New fluid everywhere as well, and I think having done this, I immediately dismissed brake sounds as a possibility?
If I had left the brakes as is, this sound would have instantly lead me to a brake pad rubbing a bit, and I think that is probably the issue. I'll be in Los Angeles on Tuesday, so can have a closer look in my daughters garage.
I have my tool roll on board, but it doesn't have everything I need to do a bearing replacement. Maybe grab some cheap tools at my daughters and replace the bearings. Tough to trust a shop, unfortunately.
Many thanks for your replies; lots of helpful info there.


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[Nick Calne]

Just let us know you got there.

[Sin_Tiger]

There are two things that I often find get overlooked with these brakes.

1) I always remove the slider plate and the rubber boots for the pins for a complete clean out including the cavity in the caliper and re-grease with CV grease which is my preference or red rubber grease should also be fine. It can come as a surprise how quickly general purpose grease can harden up if it's not kept in motion as it would be in say a bearing.

2) There is a tiny wee hole in the master cylinder that often gets missed, even old fluid can cause a restriction or blockage and once that happens it can prevent the fluid returning when you release the brake lever, it also makes it harder to bleed the system after work. The hole is only about 0.2mm so it's easy to miss but it's usually easily cleared with a strand of copper wire.

Apologies if you know about these points or have addressed them already  if you need photo's just shout.

As Nick says  ride safe 

[ssevy]

Well, today I abruptly lost the rear brake. Haven't got all the luggage off to pull the side cover and check the fluid.
Was working fine this morning, as I hardly ever use it except occasionally when trail braking or during walking speed stuff.
The disc looks really dark, so I'm wondering if my foot was resting on the pedal without me realizing it?
I was riding against very strong headwinds all day, and that feels just like a brake dragging, so who knows?
I did clean and regrease those pockets with red rubber grease, but I did not run a wire through the return holes, although I used brake cleaner and compressed air to clean the cylinders.
Engine wise, the bike has been perfect, so these issues are the adventure part of adventure traveling I guess.


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[Lee337]

Had that happen on an Aprilia RSV while away from home - much rather the back brake go than the front.

Hope you get it sorted

[Sin_Tiger]

You're right, that is almost certainly been dragging. hope you've caught it before the pads wore out or the disc got too hot    Might have been a case of the rear affecting the front after all then. The rear master has that tiny hole in it as well. 

[ssevy]

I just pumped the pedal and fluid came out the caliper, so must have ruined my new seals.
Anyone know what the t-size is for the two caliper bolts?
How about the caliper slide pin hex driver?
Another caliper rebuild I guess...


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[Sin_Tiger]

Probably more info than you need:-

Caliper Mounting Screws - M10x1.25, Torx T55, 40Nm
Pad Retaining Pins - Hex M5, 18Nm

I would say the seal failure is most likely a symptom of heat generated by prolonged pad contact and you'd best look elsewhere for the root cause of the pads not releasing. I wouldn't blame yourself for resting on the brake pedal for long enough to cause that, you've been riding the same bike for too many years and thousands of miles, I'd say it would be very uncharacteristic 

If we assume that the rim / hub is running true and the disc run out is within limits, then the other two suspects are:-

1) The caliper not being able to move on the slider pins, you've done those but worth a second look in case the prolonged heat has caused any damage. The caliper not correctly positioned relative to the disc, worth checking the reaction arm and it's retaining screws, I'd recommend some medium screw lock on the threads when reassembling. While you've got them out, also check the caliper mounting bracket, there is a bush that gets clamped when the axle is tightened up but the main part of the bracket should be free to rotate around that bush, it can only move a few mm either side even with the reaction arm disconnected as the lug that sits in the axle bobbin recess will stop it going too far. It's not likely to cause the issue you've experienced but another possible factor eliminated.

2) The next and most likely culprit is the hydraulics. Since you were able to push fluid out of the caliper it would be reasonable to assume the hose is clear. The master cylinder is the main suspect, although unlikely from what you're saying the pedal and push rod linkage is worth a looking at. My money is on the master cylinder, with any luck at all the rubber bits will still be OK but it's possible during maintenance loose debris is blocking fluid or restricting movement of the piston, a broken spring is possible but less likely. See below for my favourite suspect tiny orifice 

If you can't get genuine Triumph parts or want to save a few $, try a Honda or other Japanese parts dealers. These Nissin 27mm calipers and 14mm master cylinders were very common and still are, guess what's on the back of my Trophy 1215  the only differences were the mounting plates and bleed nipple orientation.

My preferred method of bleeding brakes in the field, is to unclip the hose as much as possible to allow the caliper to be lifted higher than the reservoir, stick a block of wood or similar in the pad gap which allows you to bleed the caliper one handed and see clearly what's happening without being on your hands and knees (mine can't take it anymore  ) and trying to put load on the pedal or lever at the same time.

I hope you find the cause quickly so that repairs don't eat into your family time, which is why you went all that way int the first place and have a good  as well of course.

[Bixxer Bob]

I boiled the rear brake on my 955 in the Alps. Long series of downhill hairpins using a lot of rear brake due to lots of gravel.  Blued the disc too.  Eventually came back to me once it called down. 

As Sin says, if the slide pins are seized, even though you cleaned the pistons, it will bind enough to to blue the disc. But it sounds like you've gone further and cooked the seals.