Hydraulic disc brakes

[benb]

I put my Spesh Crosstrail into the LBS for a service last weekend. Since I had it back, the rear disc brake is decidedly spongy. If I pull really hard on the lever, it will slow down, but it's no way near as responsive as it was before, and the front brake is still very firm.

I was planning to take it back in so they could sort it, but I'm not sure if I have the time to take it in before going on a fairly long sponsored bike ride on Sunday.

So can anyone tell me if this is an easy thing to sort out myself?

Thanks.

 

[battered]

Yes it is, sounds like they have left an air bubble in the brakes. If the spongy brake goes hard when you pump the lever (fnaar) then this is the fault. Bleeding brakes is usually straightforward, you need the appropriate fluid and a bleeding kit makies life easier. You mayneed to do it more than once, tiny bubbles can really screw up brakes, esp on bikes as the fluid volume is so low. You may need to tap the caliper to get any bubbles to come loose and go to the top so they can escape from the bleed nipple.

 

[RedBike]

They could have just changed the pads and the new pads at the back haven't been beded in / are crap.

 

[02GF74]

simple answer is fir shimano XT 4 pot ... not that it helps.

specialized - what brakes you got fitted? They were using Margura ,in my case MArta, that are nowhere near as nice to bleed as Shimano but in 2009 went over to Avids - no expereicne of those but looking at photos, they are similar to formular where there is no reservoir but a screw hole to attach one.

anyways, once I know what make/model you have fitted, I may be able to advise.

it does sound like there is air trapped.

 

[benb]

Yes it is, sounds like they have left an air bubble in the brakes. If the spongy brake goes hard when you pump the lever (fnaar) then this is the fault. Bleeding brakes is usually straightforward, you need the appropriate fluid and a bleeding kit makies life easier. You mayneed to do it more than once, tiny bubbles can really screw up brakes, esp on bikes as the fluid volume is so low. You may need to tap the caliper to get any bubbles to come loose and go to the top so they can escape from the bleed nipple.

Sounds too technical for me - I'll get the LBS to sort it.

They could have just changed the pads and the new pads at the back haven't been beded in / are crap.

I don't think so. On the front brake, it grips the disc immediately on only a small pull of the lever. On the back one, you have to pull hard to get it to do anything, and before it grips it feels very spongy. Plus they didn't charge me for any parts, so I don't think anything was replaced.

simple answer is fir shimano XT 4 pot ... not that it helps.

specialized - what brakes you got fitted? They were using Margura ,in my case MArta, that are nowhere near as nice to bleed as Shimano but in 2009 went over to Avids - no expereicne of those but looking at photos, they are similar to formular where there is no reservoir but a screw hole to attach one.

anyways, once I know what make/model you have fitted, I may be able to advise.

it does sound like there is air trapped.

According to the spec the brakes are Auriga Comp

I think that I'll get the LBS to sort it, as it was their service that caused it, and it sounds a bit technical for me.

 

[iendicott]

Ask if you can watch them bleed the brake and then you will kick yourself as it is dead easy to do.

 

[battered]

Dead easy, dead easy to get wrong too. You don't want DOT4 on your paint either, not if you like your paint.

 

[g00se]

Sounds like it needs bleeding - but it could possibly be contaminated pads not gripping the rotor properly?

 

[benb]

Sounds like it needs bleeding - but it could possibly be contaminated pads not gripping the rotor properly?

I'm note sure that would give me the spongy feeling in the lever?
I'm going to take it to the LBS in the morning and get them to have a look.

 

[g00se]

I'm note sure that would give me the spongy feeling in the lever?
I'm going to take it to the LBS in the morning and get them to have a look.

No, air in the fluid sounds the likely candidate - but when I got a tiny bit of GT85 on by front pads, it did feel a bit spongy due to amount of extra force i needed to pull them with.