Had to face my brake post mounts myself

[vertrkr]

Bike: 2021 Trek Rail 5 alloy

Short story: My rear brakes never worked well, rubbing, noisy, lack of power or uneven wear. Tried everything I know, new hardware, LBSs, nothing worked completely. Broke down and bought the ParkTool facing tool, now it's perfection.

Longer story: I've fiddled with my rear brakes for 3 years since it was new. I could eliminate one issue but another one would pop up. I tried new hardware, rotors, pads then finally new TRP DHR EVOs with no luck. I had the LBS head tech give it a shot and it was no better.

Strangely I had a dream, of all things, that my post mounts were not parallel. I didn't even know that was a thing. Researching this it is indeed a thing and a few companies sell tools to reface the mounts. ParkTool sells one, DT-5.2, for about $500.

I figured a bike shop must have this tool so I called all the LBS. Nobody had one but some offered they could eyeball it with a file. At this point I wanted it done right so I bought the damn tool myself.

I watched and read everything about how to use it as there's no turning back if you screw up. With the facing tool, cutting oil and marking dye I gave it a shot.

The best tip I found was to put the most pressure on the sliding collar down on the chrome shaft while turning the blue knob.

One post was 3mm higher out of parallelism and both tilted a few degrees. That took about 30 minutes of hand cranking, checking, cranking, praying I'm not doing it wrong.

It worked, now I have perfection. No need for conical washers as the caliper is perfectly aligned to the rotor and brakes like a dream. Happy to put this one to bed.

 

[Tony4wd]

I had a similar experience with my Cube - shops don't have a facing tool so I used a file to get the posts closer to square. At about AU$800 I can't justify the purchase of the Park Tool so I just put up with brake pads wearing on an angle. I'm surprised the shops don't have the facing tool and that they don't check the posts on each new bike.

 

[Amber Valley Guy]

There was a recent GMBN Tech video on this and the guys at Park Tool showing the DT-5.2 post mount tool. Here's a link

 

[Stihldog]

That Facing Tool! Gotta have one to eliminate any calliper alignment issues. Expensive though. Maybe next Xmas.

 

[RustyIron]

At this point I wanted it done right so I bought the damn tool myself.

I'm jealous!
I want one! But I don't want to pay.
I want to make one! But it would take a day or more.
I'm cheap and I'm lazy... I'll never own one.

What frame were you working on?

 

[Stihldog]

I want one ! But not for that price.($500+). I see a few bikes come through my cave and some of those bikes could use that tool. I’d really need to justify it though. None of our LBS’s have one.

The Park Tool Wheel Holder caught my eye. But for that price ($200), no friggen way. But one day I was surfing the Trek tool site and saw it listed for $32.
I click BUY!
It lives in my vice and I use it more than I thought.

 

[Ou812]

I’ve had the same issues on a few Fox forks but all my frame mounts have been good so far. Luckily one of the local suspension shops has the facing tool so I haven’t had an excuse to buy one probably a tool I’d hardly ever use though.

 

[Tooks]

Seeing what some folks spend on shocks and forks, £450/$500 on a precision tool that will last a lifetime doesn’t seem as outlandish as it first appears?

Misaligned and/or squeaking brakes are the bane of biking, if you go through a lot of bikes/frames/forks it could be a great tool to have around the place.

I might pick one up so myself and @steve_sordy can use it!

 

[jetskier973]

Yup, went down this rabbit hole too.
Calvin says you can't use a file. Says it will never be right if you do.
Sorry Calvin, I went ahead and used a file instead of sending you 450 greenies.
And I'm glad I did.
Now my calipers don't "walk" anymore when the wrench clicks at torque limit, all the squealing is gone, and I can set up my brakes to feel like it's the sunshine that makes them engage.

I did this work gently, deliberately, and patiently with lots of checking with straight edge, flashlight, black Sharpie, and flat file.

Would still like to have the tool as it is far closer to perfection than I can get. But I did a pretty good job imo, and I'm happy.

I wish LBS's would carry facing tools for post mounts, bottom brackets, and head sets.
Any LBS that offers this service is sure to make people very happy.

 

[vertrkr]

I'll certainly let anyone use it if you're near the East Bay Nor Cal.

I was half tempted to pay it forward and donate it to my lbs but I'm also tempted by a Gen 5 Rail when they come out.

I found a Reddit post of bike mechanics grumbling how often they have to reface mounts on new frames. One knew the head QC guy for Trek who said he had to make frequent trips to the factory otherwise things would get out of hand.