# Hydraulic brake lever squeezing more than it did before?



## hunter006 (Jan 20, 2012)

It has been 2 days since I took my bike in for a tuneup. The bike came back in basically the same condition I sent it there, but I have noticed that the left brake lever has progressively been depressing more than the right one. Since hydraulics do that auto-adjustment thing, this was unexpected. There is no "squishy" feeling, still feels solid to me, but that could be my lack of experience with these. It's also getting progressively worse.

This is the first time I've had hydraulic brakes. I'm familiar with the disadvantages of long descents, high speeds and hydraulic disk brakes doing one continuous long burn, and while I do have a few high speed descents on my commutes/rides, I don't just hold the brakes down, I squeeze-and-release them to give them half a chance to cool down, rather than continuously accumulating heat on the pads. The disks aren't showing any signs of warping, bluing or damage due to heat. From what I can see, the pads on the front are worn but not terribly so. This set up is as the bike came from the shop, and I've checked that the pads match the disk.

So, while I will take it back to the shop today to get them to look at it again, I'd like to know what the more experienced would say I should also check. I know there's an adjustment screw on the lever itself that is designed to adjust when the brakes engage relative to lever movement, so my worry is that I'll get a bad mechanic who will adjust that and say I'm fine, then I'll discover later on that the problem was in fact oil boiling off inside the braking system and introducing gas in to what should be an gas free environment. I wouldn't put it past one of the mechanics there to do that (I normally request someone else, but you get who you get...).

Thus I'd like to know what other people would do. I don't have a bleed kit (yet) but normally I'd have done that by now just for peace of mind.


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## Boulder Pilot (Jan 23, 2004)

Either purchase a bleed kit or have your shop bleed your brakes.


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## RTM (Sep 17, 2005)

I would definitely buy a bleed kit. Almost any problem at the lever that gets progressively worse can be aleviated with a proper bleed. 

If you own a kit you can do it whenever you want. You know its done right, and you eliminate the hassle and cost of trekking to the LBS. Many wins.


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## hunter006 (Jan 20, 2012)

Well, the LBS is right next door to where I work, and they did just service the bike, so trekking to the bike shop is more of a financial woe than a timely one. Good to hear that 2 from 2 responses thus far are "a bleed kit is a good idea in this situation" - at least (I think) I'm on the right track.


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## zebrahum (Jun 29, 2005)

Are you leaking fluid from anywhere? Let's be honest, if fluid isn't coming out then your lever shouldn't be migrating because of a need to bleed. A gradual progression of the lever closer to the bar with no spongy feeling is probably due to the reach adjuster (a little 2mm or 2.5mm screw you can see between the lever and the handlebar) migrating. Every Hayes brake I've ever had did this and I've seen a few models of every manufacturer that have suffered from this. A lot of times you can actually see how far the reach adjuster is threaded into the little barrel and make them even between the two levers. I would advise against hitting it with locktite unless you take it all the way apart and allow the locktite to fully dry before assembling; if you don't you risk getting locktite into places that could be dangerous if the brake isn't allowed to function properly.


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## EABiker (Jun 24, 2004)

I agree with the above post; that sounds very likely. Another possibility; are you storing the bike upside down? If so, the slight amount of air above the fluid in the reservoir could travel up the line to the caliper. Mine does this for sure.


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## zebrahum (Jun 29, 2005)

EABiker said:


> Another possibility; are you storing the bike upside down? If so, the slight amount of air above the fluid in the reservoir could travel up the line to the caliper. Mine does this for sure.


If this is the case then you usually have to pump your lever a couple times to get it to feel strong. A pretty easy diagnosis to see if that's the issue and the fix would be to bleed the brake.


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## hunter006 (Jan 20, 2012)

zebrahum said:


> Are you leaking fluid from anywhere? Let's be honest, if fluid isn't coming out then your lever shouldn't be migrating because of a need to bleed. A gradual progression of the lever closer to the bar with no spongy feeling is probably due to the reach adjuster (a little 2mm or 2.5mm screw you can see between the lever and the handlebar) migrating. Every Hayes brake I've ever had did this and I've seen a few models of every manufacturer that have suffered from this. A lot of times you can actually see how far the reach adjuster is threaded into the little barrel and make them even between the two levers. I would advise against hitting it with locktite unless you take it all the way apart and allow the locktite to fully dry before assembling; if you don't you risk getting locktite into places that could be dangerous if the brake isn't allowed to function properly.


Negative on the leaking fluid. That was the first thing I checked - all the way along the brakes, making sure to pay close attention to the seals. This being my first hydraulic brake bike, I'm not entirely sure of what to look for.

The reach adjuster thing is pretty much what the LBS mechanic said; the threading was equal on both sides as it was when I got the bike, but I'd taken it in for a service and maybe they'd fiddled with it... we're not sure, the guy that actually serviced my bike is pretty much my DFL choice for mechanics. When I got it back, the left one was further in and it seemed to get worse over the weekend (change = bad!). This morning, we didn't apply loctite, but we did adjust the reach adjuster. As you mention, it was a small allen key head, either a 2, 2.5 or 3mm (used the 3 way hex wrench). For reference, the brakes are Shimano M505 brakes.



EABiker said:


> I agree with the above post; that sounds very likely. Another possibility; are you storing the bike upside down? *If so, the slight amount of air above the fluid in the reservoir could travel up the line to the caliper.* Mine does this for sure.


I didn't understand why he asked me this question at the time, but I do now. I don't store the bike upside down, but I did flip it upside down briefly on the weekend to change a flat tire for a total of 6 minutes. Other than that, it's been shiny side up and rubber side down.



zebrahum said:


> If this is the case then you usually have to pump your lever a couple times to get it to feel strong. A pretty easy diagnosis to see if that's the issue and the fix would be to bleed the brake.


Pumping the lever didn't help. I mean, it was still this way after I got to work, which is a 20 mi ride involving a lot of hills.

Thanks to everyone that gave their suggestions. I'll keep monitoring this thread for any other information, it's been incredibly useful, especially learning that the Hayes brake thing and the issues with storing the bike upside down. This seems to have fixed the issue for now, however the LBS did give the warning that if the problem persists, the next step would probably be the bleed kit.

Here's some handy dandy photos of the reach adjust screw that we ended up adjusting. Looks like 1.5-2 threads on the left side sticking out, 3 threads on the right after adjustment.


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## hunter006 (Jan 20, 2012)

-- Post MTBR forum query follow up --
It seems that the overall brake system is *slowly* introducing air somewhere near the reservoir.

I ended up learning three different ways to get air out of the system.
*Tools:* I need a bleed kit, and some Allen keys.
*Process:* All of them start off the same way - putting the bike on an angle such that the brake lines are as vertical as possible (to assist bubbles making their way through the hose), setting the hydraulic reservoir to be level and removing the cap that covers the reservoir. It's best not to have the wheel between the brake pads because oil could get on the disk; LBS dude used a chunk of foam between the brake pads, but it had the same properties as a thin piece of wood.

*Minimally invasive time consuming option*: Actuate the lever and tap the lines every 5 minutes for around 2 hours. The tiny bubbles in the lines will slowly rise to the reservoir. Takes a long time because the bubbles get trapped at any turn in the lines (and they're very small), but uses the smallest amount of oil as you only need to top up the reservoir once. I watched a bunch of TV shows and every time there was an ad break squeezed the lever.
*Conventional process:* Attach bleed kit tube to the bleed nipple at the bottom, squeeze the lever, release the bleed nut (releases oil), tighten bleed nut (stops flow of oil), repeat until solid feel to brakes. Faster, but uses more oil.
*LBS mechanic process - "reverse" bleed: * Attach bleed kit tube to bleed nipple after making sure no air is in the tube, apply pressure to the oil bottle at the bottom while making sure the tube is secure, and squeeze oil in to the caliper while removing oil from the reservoir to stop it from overflowing. Same as #2 for using more oil.
*Post process: *Clean any oil off the system using 70% isopropyl alcohol (available from the local pharmacy; I had some on hand for medicinal alcohol).

In my case, it seems that I'm periodically getting really small bubbles in the air lines, and doing #1 every 3-4 months keeps the brakes in good working order. #2 and #3 are the full brake bleed, which is more resource consuming but will be faster.

A little more excessive than I expected (I thought I might have to do this whenever I replace the brake pads, no more frequently) but overall still in the "not too bad" category.


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