Forum home Road cycling forum Workshop

Ultegra Hydraulic Disc Brake Caliper BR-R8070 issues

Drax32Drax32 Posts: 25
edited April 2019 in Workshop
I’m installing some new front disk pads but I’m having issues with the pistons retracting back flush , I can get one side flush but pushing the other side out and vice versa .
The disk Disk rota wont fit between the new pads , my brakes are Ultegra BR-R8070 and my new pads are L04C Metal.
I recently had my cables shortened to accommodate a new handlebar do you think its possible their is too much fluid in the system after bleeding my brakes .

Posts

  • rafletcherrafletcher Posts: 1,235
    I guess if the shop (I'm assuming you didn't do it) bled the brakes with worn pads in, rather than taking them out and using a bleed block in the caliper, that could happen. Suggest you get a bleed block and bleeding kit, and have a go yourself. Remove the lever bleed screw cover, fix the bleed cup to it (for 8070 you'll need the extension tube as in typical shimano style, they've changed the thread on the lever so the standard bleed cup can't screw straight on :roll: ) then remove your pads and push back the pistons to get the bleed block in position. All you should need to do at this stage is pull the lever hard to get as much fluid in, and carefully remove the bleed cup and replace the bleed screw. Youtube will probably help, and the Dealer Installation Manual can be downloaded too.

    This is the extension tube you need https://www.sjscycles.co.uk/gear-spares ... 3ec8c25c2f

    to go with the funnel from this https://www.sjscycles.co.uk/tools/shima ... 3ec8c25c2f.

    Other retailers are available of course.

    You'll also need the appropriate allen or torx key to get the lever reservoir cap off, I can't remember which, and the bleed block of course, something like this https://www.ebay.co.uk/itm/Shimano-Disc ... Sw5VFWJQqT.

    Something to note, when trying to get the block into my 8070 calipers, I found there was a small pin in the way. No idea what it's for, can't find anything in the docs about it, but it can be pushed back into the caliper body using a blunt instrument (screwdriver blade for instance) to get the block in, and pushed back out when finished.
  • Drax32Drax32 Posts: 25
    I had a feeling the shop left my old pads in when bleeding my brakes, can't see any other reason my new pads wont fit.
    Thanks for the advice .
  • veronese68veronese68 Posts: 23,487 Lives Here
  • rafletcherrafletcher Posts: 1,235
    Actually I got my bleed kit from Epic for my other bike (can't remember but the calipers are post mount Shimano and it's got 105 levers) - and it's fine for that BUT I don't think the Epic kit will fit (as in screw into the bleed hole) the Ultegra 8070 levers, hence my buying the adaptor and fluid pot as additions.
  • kajjalkajjal Posts: 3,380
    It sounds like there is too much fluid in the system, this is not uncommon on new bikes. Start by making sure there is nothing behind the pads like a small stone reducing the gap between the pads.

    Then try very gently pushing the pads apart once installed with a large flat headed screwdriver. If the rotor still won’t fit then next with someone helping you remove the bleed screw on the shifters. Then gently push the pads back and hold them back, at the same time the other person screws the bleed screw back in catching any fluid released with kitchen roll. Once screw is tight let go of pads, refit wheel and after riding the bike & braking a few times you should be fine.

    If pads still rub just loosen bolts on brake calliper slightly, pull brake on & hold on, tighten bolts and release brake. Again ride bike and brake a few times.

    Just be careful to do it slowly and gently or you may lose too much fluid and get air in. This would then need a bleeding kit.
  • veronese68veronese68 Posts: 23,487 Lives Here
    rafletcher wrote:
    Actually I got my bleed kit from Epic for my other bike (can't remember but the calipers are post mount Shimano and it's got 105 levers) - and it's fine for that BUT I don't think the Epic kit will fit (as in screw into the bleed hole) the Ultegra 8070 levers, hence my buying the adaptor and fluid pot as additions.
    Sorry, having posted the link I noticed it does say on the Epic site that you need that adaptor for some brakes including the R8070. Still worth it I think as I find the Epic kit with two syringes easier to use. I bought a universal kit as I fitted a used Parabox convertor on my bike, I already had the funnel from doing the brakes on my MTB. Haven't used the funnel on anything since getting the Epic kit.
  • Drax32Drax32 Posts: 25
    Its worth mentioning I'm trying to fit different shimano pads ( L04C Metal ) instead of the L02A Resin pads that was fitted as standard .

    According to Shimano L04C Metal pads are compatible , Could this be my problem ?

    https://bike.shimano.com/en-EU/product/ ... 070-F.html
  • whyamiherewhyamihere Posts: 7,412
    Drax32 wrote:
    Its worth mentioning I'm trying to fit different shimano pads ( L04C Metal ) instead of the L02A Resin pads that was fitted as standard .

    According to Shimano L04C Metal pads are compatible , Could this be my problem ?

    https://bike.shimano.com/en-EU/product/ ... 070-F.html
    That's not the problem. They start at the same thickness regardless of compound.
  • Drax32Drax32 Posts: 25
    Managed to fix it , done what Kajjal advised and took my time . Thanks to everyone for your help.
  • kajjalkajjal Posts: 3,380
    Drax32 wrote:
    Managed to fix it , done what Kajjal advised and took my time . Thanks to everyone for your help.

    Good to hear, disk brakes tend to be pretty much fit and forget once set up right.

    The main problem they get is contamination from oil or similar, often if the chain has too much lube on it spraying the excess all over the rotor & calliper. As long as that is avoided they are fine.
  • damianshepdamianshep Posts: 1
    Sorry to reignite this but I seem to have had the same problem. I have managed to get the sticky piston back in but have lost all pressure in the system.. this is driving me bonkers, I’ve had no issues with 105 previously but these Ultegras are frying my head.. please help...
  • pilot_petepilot_pete Posts: 1,982
    When you say ‘got the piston back in’, it sounds like you managed to pop it out by applying the brake with no pads in? The whole system will need re-bleeding. Start by forcing the pistons apart fully with the bleed screw out of the lever (so you are not pushing against air). Put in the bleed block.

    I use the Epic syringes. Put the empty one at the lever, fill the other one and force the fluid up from the caliper, gently until the fluid emerging from the lever end is bubble free. It helps to have the caliper as low as possible and a complete ‘uphill’ run to the lever (especially a back brake).

    Now follow the instructions to remove any remaining air from the caliper end. Syringe at the lever should have plenty of clean fluid in it. Put the hose on the bleed nipple at the caliper and the other end into an small plastic bag, using an elastic band to hold it onto the pipe.

    Now open the bleed nut in a quick burst whilst pulling the lever. It is a quick open and close, just to get a ‘squirt’ of fluid out. Keep doing this until the fluid coming out has no bubbles of air in it. Make sure the syringe at the lever never runs out of fluid or you will start sucking air back in that end!

    Once the air is all removed check the lever feel. It should be solid and not pull all the way to the bars. A couple more blasts on the bleed nut can help stiffen up the feel if required. Once it is solid you are there, apart from adjusting lever throw and biting point adjustments as necessary (especially if these have never been done before).

    Clean everything off thoroughly ensuring there are no traces of fluid around the caliper or oozing down the sides of your lever under the hood. Replace your pads, ensure your disc rotor is clean using isopropyl alcohol and that’s it.

    It can help sometimes to leave the bike in a position to keep that uphill slope from caliper to lever, and leave the lever applied with a rubber band overnight if you just can’t seem to get all the air out. The next day you should find the bubbles at the top in the lever, so a quick bleed can expel it - you will only need a little bit of fluid to expel the few bubbles that were left.

    PP
Sign In or Register to comment.