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Old 31st March 2020, 22:00   #1
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Screechophobia! Solving brake-screeching noise on my MTB

She's been a companion, indeed, for the last five years. Rain, sun, slush, muck, you name, it's been though it all. Surprisingly, she's been through it all, and aged like a fine wine.

Screechophobia! Solving brake-screeching noise on my MTB-46170081_10217334022087284_3584243649820491776_o.jpg

Circa 2015, I laid my eyes on, it was love at first sight. The FOCUS MTB. Genuine German made Chassis with excellent hardware. The one proposition that I really wanted from my earlier experience were good quality hydraulic disc brakes and front suspension. My earlier bikes were disc brakes too, but were cable operated.

Cable operated disc brakes. Anyone who had owned a cable operated disc brake bike know how they were a slouch, grabby, excellent at brake fade, and grabs and locks when you least expect. I was almost toppled countless times, before I knew the grabby nature and almost developed another motor skill to undo the locks on the run. Truly were disgrace to a good chassis.

Coming to this, my priorities were either Shimano, Tektro or SRAM. SRAM weren't available, Shimano had a model that I didn't like, the tactile feel and the quality wasn't, according to me great. Then I found out this, me creaking my eyes to see this one, in the dark, away from consumers, one made with Tektro/TRP brakes. Sweet!

Did a half baked U circle in front of the shop, and that's it. Flabbergasted is a mere word I can say for those fantastic brakes. Super sharp and precise, superb lever feel, and it would put most motorcycle bikes' brakes to shame with panache. I truly mean that, when I say this.

Stoppies, stoppies and stoppies, as much as I remember, the beating this bike took from me would be an understatement. Heck, the brakes made me do it, time after time after time it was purely for the brakes alone I did it. Brake fade! Nada! Screeching sounds, zilch, rotor heated up, yes sir it did. Did I try to touch the hot rotor and got the banana? Yes, sir was served hot.

Tektro and most bicycle hydraulic systems, use mineral oil and not the normal brake fluids, i.e. the DOT series. One of the reason the brake fluid remained in pristine state was, the mineral oil is almost 100% hydrophobic, and it was pleasing to see the innards of the reservoir is a clean shape.

Of late, after my accident, the bike was parked a long time without a proper ride or care though was covered neatly. Apart from the deflated tires, and web mounds, it was pristine for the most part. There are times, it makes me believe, like it was purchased just yesterday, after all these years of abuse.

Due to my ongoing physio session, the doctor advised me to take to cycling again, and hence she was brought back to life. Washed, lubed, and went for a small limping ride, inside our portico, and the front was as good as it was new, but the rear had been accustomed to a new phobia -- the screechophobia, as I call it.

My first gumption was a bad brake fluid, after all, it's 5+ years and who in their right minds would keep a fluid running that long. Unfortunately, circumstances in my case did yield to that exact scenario, and lucky I did stack 100 ML of Mineral Oil I a year or so back, the OE TEKTRO ones I got for Rs. 350 odd. To my surprise, after opening the reservoir, the stock fluid is was in excellent shape. I couldn't snap the pictures for this. I apologize, which I really wished I did, while writing this article -- was too keen on the operation.

Bled the brakes, took 15 minutes for both the brakes, with the kind help of my mum, and back I was into circles and boom, the screechphobia, on the rear returns. Wore my torn surgical gloves, and it was time to remove for a laparoscopy..

Tools required!
5 mm allen key (For caliper bolts)
3 mm allen key (For pad and spring holder bolt)
Screechophobia! Solving brake-screeching noise on my MTB-10.jpg

The caliper with the 5 mm allen bolts removed and caliper carrier.
Screechophobia! Solving brake-screeching noise on my MTB-5.jpg

The innards of the caliper. Truly surprised by the condition it was at. Though, you can see rust formation on the lip of the caliper piston.
Screechophobia! Solving brake-screeching noise on my MTB-3.jpg

Screechophobia! Solving brake-screeching noise on my MTB-9.jpg

Next up, it was removing the brake pads, pad spring and holder bolt, the small 3 mm lengthy bolt as shown in the first pic which slides through all these three and makes a solid, perfect fix.
Screechophobia! Solving brake-screeching noise on my MTB-7.jpg

Screechophobia! Solving brake-screeching noise on my MTB-8.jpg

The 3 mm Allen Key holding the spring, and pads in place.
Screechophobia! Solving brake-screeching noise on my MTB-28.jpg

Looking at the brake pads, I did find something interesting. These weren't ordinary organic brake pads, these were semi-sintered brake pads. Though the website claims these to be ceramic pads, I have my doubts on that. (Probably newer models use ceramic, I guess) But, from my experience, it definitely seems like a semi-sintered brake pad and had decent amount of pad material left.
Screechophobia! Solving brake-screeching noise on my MTB-11.jpg

A comparo of the pad, as removed from the caliper on the right and the one sanded with mild grit sand paper on the left.
Screechophobia! Solving brake-screeching noise on my MTB-15.jpg

After sanding both. If you'll look closely, you can see the copper particles fused with the pad. Excellent quality pads to be honest!
Screechophobia! Solving brake-screeching noise on my MTB-16.jpg

Now, with the pads sanded. Next step was to clean the pad springs, caliper innards and pistons. I did use a Scotchbrite scrubber to clean it. This scrubber is stubborn yet is soft on the caliper's superbly finished aluminum housing. Cleans mucks very neatly, with the help of brake cleaner. No scratches!
Screechophobia! Solving brake-screeching noise on my MTB-13.jpg

Some brake cleaner and brushing the innards of the caliper.
Screechophobia! Solving brake-screeching noise on my MTB-17.jpg

Scotch-brushing the caliper. They come out great!
Screechophobia! Solving brake-screeching noise on my MTB-18.jpg

Screechophobia! Solving brake-screeching noise on my MTB-20.jpg

Installation of everything back together was pretty much an easy job. But, there were things that one really needs to take into account such as these. First off, the bolts that were from the factory were Loctited, all the bolts, the caliper holder bolts, the pad/spring holder bolts were all Red and Blue Loctited. I did have both colored Loctites with me, and used them wherever necessary.

Starting off with applying anti-seize grease on the back of the pads. This really helps eliminate piston rusting as mine had mild piston rusting, and pad sticking to pistons.
Screechophobia! Solving brake-screeching noise on my MTB-24.jpg

Carefully installing the pads so that the grease doesn't end up on the pad material. This was quite tricky.
Screechophobia! Solving brake-screeching noise on my MTB-25.jpg

The pad spring and the pads seated perfectly, it was a little tricky taking this photo, as the springs and pads undid almost immediately turning it down, and there I had to cup my hands to get photo of the seat-ment!
Screechophobia! Solving brake-screeching noise on my MTB-26.jpg

Loctited the pad bolts with Medium Strength Anabond and torqued the 3 mm bolt, all the way in. Bajaj should learn how to make quality bolts from Tektro.
Screechophobia! Solving brake-screeching noise on my MTB-22.jpg

Screechophobia! Solving brake-screeching noise on my MTB-27.jpg

Red Loctite for the Caliper Bolts.
Screechophobia! Solving brake-screeching noise on my MTB-30.jpg

Caliper being installed on the caliper carrier.
Screechophobia! Solving brake-screeching noise on my MTB-31.jpg

Screechophobia! Solving brake-screeching noise on my MTB-32.jpg

All fixed up!
Screechophobia! Solving brake-screeching noise on my MTB-33.jpg

Ride Impressions! Did it solve the issue?

The brake feel has surprisingly gotten back to the hard, firm and progressive feel. This isn't used to be the case, till this laparoscopy. The rear is eager to anchor hard with a little pressure, and goes into supermoto mode, like when I had experienced long back. The squeaks are present albeit extremely, extremely feeble. The lo, juddery screechophobia, for now, seems to have vanished.

The front anchors so hard, and has the throw you away attitude, with a little force, just the way I like it, and how an MTB's brake should be. Happy with those, again, for now.

In the hope, it will be of help to somebody.

Cheers!
VJ

Last edited by Aditya : 2nd April 2020 at 14:19. Reason: Formatting
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Old 27th April 2020, 21:12   #2
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Re: Screechophobia! Solving brake-screeching noise on my MTB

Quote:
Originally Posted by VijayAnand1 View Post
Cable operated disc brakes. Anyone who had owned a cable operated disc brake bike know how they were a slouch, grabby, excellent at brake fade, and grabs and locks when you least expect.
VJ, I ride a bike with mechanical disc brakes.
Haven't noticed any screeching or grabbing with the brakes yet - they seem to be working fine even when I'm zooming down the slope of a bridge.
Maybe some lubing, or adjustment issues with your previous cable operated brakes? Just wondering.

Quote:
Originally Posted by VijayAnand1
In the hope, it will be of help to somebody.
It most definitely is very helpful. Thank you for posting this detailed write-up.
aah78 is offline   (1) Thanks
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