Adding Shimano Deore BR M165 onto a GT... somethings not right.

[Matuka]

I have a GT Karakoram that had promax decipher Hydraulic brakes. They were getting old and sticky so I bought a pair of  Shimano Deore BR M165 levers and calipers. I have mounted and replaced the fluid and the brakes themselves work fine (they open and close), the only problem is there is a terrible squeal (from the rear brake) when I brake even at crawling speed. Looking closely it seems that when the brakes engage they bend the disk slightly. I have tried multiple methods of lining up the calipers but no joy. I have a 160 promax disk and to my eye the caliper pads and disk line up well. Am I being thick here do i need a special mount for the shimanos or is it a case of the promax disk not being compatible with the shimanos?

I have attached a pic of the rear calipers as they are mounted. Any help will be appreciated!

[Pulse]

To get the alignment a bit better, you can loosen the bolts slightly (untill you can move the calipers), engage the brake, and then tighten bolts while brake is engaged.

 

As for the squeal...

- Some rotors just squeal

- Clean rotors with alcohol/brake cleaner or similar

- Allow the new pads time to bed in, you can put some sandpaper to it to roughen them up a bit

[RobertWhitehead]

I take it you took the same rotors which were used with the original brakes? 

 

See, a rotor and pad seeds together when both parties are new, now once you put a new pad / brake together with an old rotor then it doesn't quite gel right. You need to clean the surface area of the old rotor. Use like a P800 (really fine) grid sanding paper and sand the rotors until it returns to its original color. The rotor will currently have a darker or black tinge to it. 

[Matuka]

To get the alignment a bit better, you can loosen the bolts slightly (untill you can move the calipers), engage the brake, and then tighten bolts while brake is engaged.

 

As for the squeal...

- Some rotors just squeal

- Clean rotors with alcohol/brake cleaner or similar

- Allow the new pads time to bed in, you can put some sandpaper to it to roughen them up a bit

 

 

Thanks for the reply. The rotor is quite old so might need to replace it. My worry was that I needed an adapter of something simple that I was missing. 

I will try some sandpaper tonight as well.

[Matuka]

I take it you took the same rotors which were used with the original brakes? 

 

See, a rotor and pad seeds together when both parties are new, now once you put a new pad / brake together with an old rotor then it doesn't quite gel right. You need to clean the surface area of the old rotor. Use like a P800 (really fine) grid sanding paper and sand the rotors until it returns to its original color. The rotor will currently have a darker or black tinge to it. 

Yup I did use the old one. Thanks this makes sense and is in line with what Pulse recommended.

I will try tonight. Thanks! 

[dirtypot]

If your brakes are screeching even at very low speeds then it may be that your pads are contaminated, especially if you dribbled any fluid while bleeding. 

[Matuka]

If your brakes are screeching even at very low speeds then it may be that your pads are contaminated, especially if you dribbled any fluid while bleeding. 

 

....I may have done...

[RobertWhitehead]

This may sound like a Suzelle does DIY or something but there is a solution to get the contamination out of the pads: 

 

Put them in the oven for 5-10 min at like 180 deg 

 

 

....I may have done...

[Matuka]

This may sound like a Suzelle does DIY or something but there is a solution to get the contamination out of the pads: 

 

Put them in the oven for 5-10 min at like 180 deg 

 

Sounds crazy but I'll give it a try! 

[nick_the_wheelbuilder]

Brake squeal is almost always a sign of pad or disc contamination.

 

When it happens to me I scrub the pads with Clean Green and use brake cleaner on the discs. This works sometimes. Other times you need to buy new pads.

[Matuka]

Brake squeal is almost always a sign of pad or disc contamination.

 

When it happens to me I scrub the pads with Clean Green and use brake cleaner on the discs. This works sometimes. Other times you need to buy new pads.

 

Brake squeal is almost always a sign of pad or disc contamination.

 

When it happens to me I scrub the pads with Clean Green and use brake cleaner on the discs. This works sometimes. Other times you need to buy new pads.

 

 

Going to try clean them first and then bake them. My oven isnt working so going to put them in the microwave on high for a few minutes. 

[dirtypot]

Going to try clean them first and then bake them. My oven isnt working so going to put them in the microwave on high for a few minutes. 

 

Metal + microwave = bad idea

[Matuka]

Metal + microwave = bad idea

 

 

Hahaha I was joking....

[Matuka]

Just an update. While cooking dinner last night I put the brake pads in the oven as per the suggestions on here. The bad news is I forgot about it and burnt the chicken, the good news is the pads came out smoking and when I put them on the bike this morning no more squeal! I'm quite amazed actually thanks for the advice chaps!

[RocknRolla]

Rather burnt chicken than, overcooking a corner due to bad brakes...

[RobertWhitehead]

Mooo-ha-ha-ha-ha (that's an evil laugh for those who's wondering) 

 

I'm glad it worked and that you're now back on your bicycle  . All the best! 

 

Just an update. While cooking dinner last night I put the brake pads in the oven as per the suggestions on here. The bad news is I forgot about it and burnt the chicken, the good news is the pads came out smoking and when I put them on the bike this morning no more squeal! I'm quite amazed actually thanks for the advice chaps!