Do I need to bleed the brakes?

[dan1977]

The pads started to stick on my front disc, so I adjusted them using the losen the screws/hold brake lever method.

This worked and the pads no longer rubbed with disc level between, however since doing this the hyrdraulic brakes (tiagra shimano on trek domane sl4) have gone very spongy and stopped working. I pumped the lever a few times and it managed to work back , maybe 50% level of what it normally is (the lever can be pulled all the way back)
do I need to bleed the brakes? maybe buy a kit. Or is there something else I can adjust to get it working again.

 

[Big John]

I've got hydraulic disks on my mountain bike and there's not much adjustment you have to do with them other than replace pads when worn or bleed them when they go spongy. When was the last time you had them bled? It certainly sounds like they need bleeding. There are many YouTube videos to help you but you will need a bleeding kit and the correct brake fluid if you choose to do it yourself. Failing that it's a trip to your lbs.

 

[dan1977]

Hi John, bike was new last May so not bled the brakes yet. Pads look fairly good too, probably air has got into it somehow.

 

[Drago]

When did you last give them a fluid change? Bleeding old fluid wont work for long, if at all.

If its more than a couple of years old then its time to whip the caliper off for a thorough cleanse, then new fluid. Mineral fluid can be funny stuff - DOT fluid degrades progressively, but mineral seems to drop off a cliff and go spongy and horrible quite abruptly.

 

[dan1977]

Not bled brakes before, this kit looks like the right one for Tiagra hydraulic https://epicbleedsolutions.com/coll...EVF7zEcLVTRoIUELjm72CTlAXzbjXa0aAmILEALw_wcB#

 

[Chislenko]

Thank the lord!!

 

[Ming the Merciless]

Not bled brakes before, this kit looks like the right one for Tiagra hydraulic https://epicbleedsolutions.com/coll...EVF7zEcLVTRoIUELjm72CTlAXzbjXa0aAmILEALw_wcB#

Take pads out before you bleed brakes and make sure disc rotor no where near. You don’t want to get them contaminated with oil. The epic kit comes with a bleed block you insert. Have a small Tupperware box to hold the small bits you remove. Take your time to get back that nice firm brake lever feel. The key is getting any bubbles out of the calliper and hose. Have a cloth available to quickly mop up any spilt brake fluid / oil.

 

[cosmicbike]

I just learnt how to do them myself, I used the EpicBleed kit linked up thread. Only difference is I haven't used Shimano oil, just regular mineral fluid from the car spares shop. Don't be tempted with any 'Dot' fluids in Shimano, they knacker the seals apparently. Once I had the hang of it, bleeding each brake is a 5 minute job.

 

[Big John]

LHM Fluid Plus mineral oil (for mineral oil hydraulic braking systems) is allegedly the same as Shimano stuff apart from being a different colour. If you've got a car spares shop nearby they probably stock it 👍

 

[I like Skol]

Did you turn the bike upside down at all while working on the caliper alignment? If you did it sounds like you have got air into the system as nothing else you have done should result in spongy brake lever feel.
If the bike is only a year old and pads still have plenty of meat remaining then there should be no need to bleed the brakes, except for the fact they have now somehow got air in them.

 

[dan1977]

That's a good point last weekend I tipped the bike upside down to clean it ready for Spring rides (had bit of muck from winter)
(Not during fiddling about with brakes though.) But was recent so highly likely , also jolted it on a pothole a few days before hand so that might have shaken up the system.

 

[iluvmybike]

Shimano is a mineral fluid sop should only need redoing every 3-4 yrs as a routine.

 

[I like Skol]

also jolted it on a pothole a few days before hand so that might have shaken up the system.

I do MTB type rough stuff on my Ultegra hydraulic brakes. A bit of rough treatment isn't a problem. Sounds like the upside down bit is the issue. You can sometimes get the bubble to head back to the lever and into the reservoir with a bit of bike orientation magic, probably difficult if it has got as far as the caliper pistons though.

Sometimes have to do this with my mtb after transporting it on it's side in the car. Put the effected lever at the high point and give it a few squeezes then it's good to go again.

 

[Kajjal]

If there is any air in the system turning the bike upside down and back upright again will give squishy brakes until it settles. A few pulls on the brake lever is enough. If there is a lot of air in the system this will not work. Epic solutions website shows how to a top up bleed to force air out and also a full bleed if the fluid has expired or it is easier due to the amount of air in the system. In my experience their kits are very easy to use.

 

[dan1977]

Thanks, I have tried pulling lever with the bike at 45degree angle downwards this morning and that has improved quite a lot maybe 80% back to what it was. Have ordered the epic kit , so will try the top up first before full bleed. From the youtube videos i've watched to try remedy it deffinitely looks like air has got into the tube.