Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Bicycle Mechanics (https://www.bikeforums.net/bicycle-mechanics/)
-   -   Problems with brake bleed (https://www.bikeforums.net/bicycle-mechanics/1227462-problems-brake-bleed.html)

goldfinch 04-04-21 04:31 PM

Problems with brake bleed
 
I have a 2014 Mountain bike with hydraulic Shimano SLX brakes. Brakes never bled. Mushy lever on rear brake. friend suggested that I bleed the brake as pad change didn't cut it. I bought a bleed kit and watched all sorts of videos. I had a total failure. I first thought I would just use gravity to drain the fluid. Well, fluid hardly drained. So I started over and tried sending fluid from the caliper port to the little cup on the brake lever. I could not push out any fluid from the syringe.

Ideas?

This is very frustrating as of the zillions of videos I could find none dealt with problems in bleeding brakes.

cxwrench 04-04-21 05:15 PM

Obviously the bleed port on the caliper has to be open and the plug has to be out of the cup. Right? Otherwise there is absolutely nothing that should stop you from pushing fluid up for the caliper through the lever. It's very simple and problems like this are exceptionally rare.

goldfinch 04-04-21 05:29 PM

I know, I know. I meticulously followed instructions. Top port open, cup screwed in, plug out. Bottom port opened after attaching hose. First opened 1/8 turn, went as far as 1/2. Syringe moved nothing.

cxwrench 04-04-21 05:38 PM

Open the caliper bleed screw more. I usually open them 3/4 to 1 turn. I NEVER drain the fluid out through the caliper, I ALWAYS push fluid up from there to the lever. Then I close off the caliper and 'burp' the lever by repeatedly squeezing the lever w/ the cup installed and some fluid in it so I can see the bubbles of air come out.

ETA: I know this sounds stupid but I've done it and seen others do it...make sure the cup is actually on the lever that's connected to the caliper you're putting the syringe on. I've put the syringe on the rear caliper and then put the cup on the front lever. That NEVER works :roflmao2:

goldfinch 04-04-21 05:52 PM


Originally Posted by cxwrench (Post 22000165)
Open the caliper bleed screw more. I usually open them 3/4 to 1 turn. I NEVER drain the fluid out through the caliper, I ALWAYS push fluid up from there to the lever. Then I close off the caliper and 'burp' the lever by repeatedly squeezing the lever w/ the cup installed and some fluid in it so I can see the bubbles of air come out.

ETA: I know this sounds stupid but I've done it and seen others do it...make sure the cup is actually on the lever that's connected to the caliper you're putting the syringe on. I've put the syringe on the rear caliper and then put the cup on the front lever. That NEVER works :roflmao2:


Open a full turn, nothing. Yeah, it is the correct lever.

goldfinch 04-04-21 07:06 PM

I can't think of a thing to do here. Make sense to spend $50 for a replacement rear brake lever/cable/caliper set? Or is there something else short of that to try first? Like disconnecting cables and seeing if fluid goes through? I am not sure what I would do if it did or didn't though.

Canker 04-04-21 08:22 PM

Take the bleeder out completely and blow through it, or use carb/brake cleaner or a can of compressed air or air compressor. Probably too tiny to blow through with your mouth. If nothing else swap bleeders front to back.

goldfinch 04-04-21 08:48 PM


Originally Posted by Canker (Post 22000400)
Take the bleeder out completely and blow through it, or use carb/brake cleaner or a can of compressed air or air compressor. Probably too tiny to blow through with your mouth. If nothing else swap bleeders front to back.

I'll try this next.

goldfinch 04-04-21 09:29 PM

I cleaned the bleeder. Didn't work. I swapped bleeders with the front brake. Didn't help, still can't push syringe. I ended up with a nice explosion of mineral oil by pushing too hard. Dang it.

Badger6 04-06-21 09:05 AM

Is the brake hose kinked? It can happen. If it is, replace it, then follow the process for fill/bleed.

goldfinch 04-06-21 11:08 AM


Originally Posted by Badger6 (Post 22002585)
Is the brake hose kinked? It can happen. If it is, replace it, then follow the process for fill/bleed.

I checked for line damage and kinks early on.

Badger6 04-06-21 11:33 AM


Originally Posted by goldfinch (Post 22002863)
I checked for line damage and kinks early on.

👍🏻

Thereís another thread (also in the mechanics sub-forum) where another person ended up having a blockage in their lever, and I think they had to have it replaced. Iíll see if I can find it when I get home and Iíll link it for you if you havenít seen it yet.

Badger6 04-06-21 02:04 PM


Originally Posted by goldfinch (Post 22002863)
I checked for line damage and kinks early on.

I found it, check it out here. But, it's for road disc...the only takeaway I get that could maybe be similar, is something inside the lever or caliper that is blocking the fluid passages. I dunno.

goldfinch 04-06-21 11:08 PM


Originally Posted by Badger6 (Post 22003104)
I found it, check it out here. But, it's for road disc...the only takeaway I get that could maybe be similar, is something inside the lever or caliper that is blocking the fluid passages. I dunno.

Thanks for the link. my hunch at this point is that it is something in the lever. In the interest of getting on the mountain bike before I head back north I ordered a replacement rear brake system (lever, cable and caliper) . When it gets here I am going to take apart the old one and see if I can at least figure out what happened.

Amt0571 04-07-21 04:23 AM

I only had this issue with Avid Elixir 3 brakes years ago. The lever was damaged.

If fluid is not pushing through, I would disassemble the lever/caliper it and see what is blocking it.

It's messy, but being a Shimano brake, at least you're not dealing with corrosive fluids.


All times are GMT -6. The time now is 07:39 AM.


Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.