Nublust Posted February 2, 2014 Author Share Posted February 2, 2014 Well I'v spent the last two hours trying to get the dust seal in, the bugger just won't go in. It seems like it's too big, but it's exactly the same size as the one that came out. I get most of it in but it forms a sort of arc, then as I push it in the arc just moves around the seal. It's driving me crazy. I've soaked it in brake fluid as well. Quote Link to comment Share on other sites More sharing options...
GazW Posted February 2, 2014 Share Posted February 2, 2014 Well I'v spent the last two hours trying to get the dust seal in, the bugger just won't go in. It seems like it's too big, but it's exactly the same size as the one that came out. I get most of it in but it forms a sort of arc, then as I push it in the arc just moves around the seal. It's driving me crazy. I've soaked it in brake fluid as well. Have you tried putting the seal on the piston a bit further down than where it would sit normally , then inserting the piston into the caliper body? You may find this will help as the inside circumference of the seal will be tensioned over the outside circumference of the piston. Quote Link to comment Share on other sites More sharing options...
mattycoops43 Posted February 2, 2014 Share Posted February 2, 2014 Well I'v spent the last two hours trying to get the dust seal in, the bugger just won't go in. It seems like it's too big, but it's exactly the same size as the one that came out. I get most of it in but it forms a sort of arc, then as I push it in the arc just moves around the seal. It's driving me crazy. I've soaked it in brake fluid as well. Have you tried putting the seal on the piston a bit further down than where it would sit normally , then inserting the piston into the caliper body? You may find this will help as the inside circumference of the seal will be tensioned over the outside circumference of the piston. I don't understand this? The seals in calipers are square section and 2-3mm deep. If you put it on the piston it will just slide up the piston as you slide it in. It may be you have got too much brake fluid on and it is sitting behind the seals pushing them out. they dont need fluid all over, just wipe them dry, try to refit, then wipe the rubber grease or brake fluid onto the exposed surface before sliding pistons in. Quote Link to comment Share on other sites More sharing options...
megawatt Posted February 2, 2014 Share Posted February 2, 2014 ABR wrote "Have you tried putting the seal on the piston a bit further down than where it would sit normally , then inserting the piston into the caliper body? You may find this will help as the inside circumference of the seal will be tensioned over the outside circumference of the piston." ??? If the seal isn't fully bedded into the calliper, you can't push the piston through it!! You certainly can't fit it using that method.!OP, make sure the grooves in the calliper are perfectly clean, with no dirt or oxide in the bottom of the grooves. The seals are a precise fit and a little bit of crud will stop them seating. You will always get an arc when fitting them, just push the arc in and the seal will be seated properly. Do not refit pistons unless they are perfectly clean, highly polished and smeared with red rubber/caliper grease. If you still struggle, pm yer number and I'll talk you through it. Quote Link to comment Share on other sites More sharing options...
Nublust Posted February 4, 2014 Author Share Posted February 4, 2014 Well I finally managed to get the seal in, I got a thin headed screwdriver and dug loads of crud out of the groove and then it went in fairly easily.Next problem is bleeding it. Did it for a while yesterday but couldn't build up any pressure. Tied the lever back overnight but still nothing this morning.I swear I'm cursed. I might try gingerly riding it with only rear brake to a mechanic that lives near me and see if I've done something wrong. Quote Link to comment Share on other sites More sharing options...
Nublust Posted February 4, 2014 Author Share Posted February 4, 2014 So I hit it with a rubber hammer, loads of air suddenly came out, now it's braking fine.+1 for brute force. Quote Link to comment Share on other sites More sharing options...
DreamytimeEscorts Posted February 4, 2014 Share Posted February 4, 2014 Adjust the clutch and use exhaust bandage. Quote Link to comment Share on other sites More sharing options...
Nublust Posted February 4, 2014 Author Share Posted February 4, 2014 That's tomorrows job. Going to try and bleed the brake a bit more as well, I've been out for a ride and it seems a little weak. I can't pull the lever right down to the handlebar though so I'm not sure whether or not I'm just used to stronger brakes on a car or something. Quote Link to comment Share on other sites More sharing options...
DreamytimeEscorts Posted February 5, 2014 Share Posted February 5, 2014 Are you sure the pads don't need replacing? As the pads wear, fluid in the reservoir drops/cables get longer which will cause the lever to move closer to the bars. Quote Link to comment Share on other sites More sharing options...
Nublust Posted February 5, 2014 Author Share Posted February 5, 2014 Aye still a few mm left on it. Quote Link to comment Share on other sites More sharing options...
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