Brake bleeding-was the wrong fluid used?

ryckee

New Member
Hi there,
My brakes were in need of bleeding and I was going to do the task myself but found that when I went to bleed them I didn't have the correct attachment piece (I have the sram guide R brakes on my mountain bike). I took it into a shop and had them done. When I got it back they still seemed pretty unresponsive especially in the rear... I had the lever almost all the way to the bar before I was getting good braking. I decided to re-bleed them myself after ordering the correct attachment piece. When I bled them I was getting out oil looking bubbles into the syringe. I was just wondering if this is normal. It looked like oil and water, not mixing together. The brakes take DOT 4 or 5.1 and I was putting 5.1 in them. I checked to make sure 4 and 5.1 could be mixed prior to bleeding them just bc I didn't know what they used at the shop. My concern is that the shop used mineral oil instead and thats why they aren't mixing. Is there any way to tell? Its been a while since the shop did the work so I don't think they would be able to tell me if they made a mistake. They are also out of town from where I live so couldn't take it back into them. Thanks!
 

Phaeton

Grumpy Old Barstool
Location
Oop North (ish)
Are you sure they are oil bubbles & not air bubbles which would explain the spongy brakes?
 

Drago

Flouncing Nobber
Location
Poshshire
The typical brake mineral oil is a distinct pinky colour, so if the wrong stuff had been used youd see it pretty quick.
 
Location
Loch side.
Hi there,
My brakes were in need of bleeding and I was going to do the task myself but found that when I went to bleed them I didn't have the correct attachment piece (I have the sram guide R brakes on my mountain bike). I took it into a shop and had them done. When I got it back they still seemed pretty unresponsive especially in the rear... I had the lever almost all the way to the bar before I was getting good braking.
What you are describing is a lever reach problem, not a bubble problem. To confirm: does the lever "harden up" after a few pumping pulls on the lever? If it still only makes contact towards the end of the lever's travel after pumping the lever, it is a reach issue, not a bubble issue.


I decided to re-bleed them myself after ordering the correct attachment piece. When I bled them I was getting out oil looking bubbles into the syringe. I was just wondering if this is normal. It looked like oil and water, not mixing together.
I can't figure out what this means. The syringe would have been filled with the stuff you were putting in, not taking out? Where were these bubbles and please describe them in terms of size, appearance etc.


The brakes take DOT 4 or 5.1 and I was putting 5.1 in them. I checked to make sure 4 and 5.1 could be mixed prior to bleeding them just bc I didn't know what they used at the shop. My concern is that the shop used mineral oil instead and thats why they aren't mixing. Is there any way to tell? Its been a while since the shop did the work so I don't think they would be able to tell me if they made a mistake. They are also out of town from where I live so couldn't take it back into them. Thanks!
It is very easy to tell if it is oil or DOT fluid. DOT fluid will dissolve in water whilst oil will float on top. Take a sample and do the experiment.
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
As has been said, both are quite different fluids. Oil is 'oily' on the skin and a pink colour. Dot is clear, and not particularly pleasant on the skin- somewhat 'tacky' unlike an oil (if you get what I mean). Plus it smells completely different.

If oil has been used, you'll find your seals will perish, so you'd see leaks.

Sounds like the Guides weren't bled properly.

Take a look at Epic Bleed Solutions - they have some spot on instructions on the bleed and exactly what to do. It's a doddle. Guide R's do pull further to the bar than RS's.
 
OP
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ryckee

New Member
Thanks everyone for the replies. Im sure that its not air bubbles. I kept the fluid and its definitely still separated. When I bled the brakes I had a syringe attached at top and bottom and pushed fluid from top syringe into the bottom...old fluid being pushed out, new fluid coming in. The old fluid did not appear pink, but at points it had a black tinge to it (I've been told this is normal with older brake fluid coming out). The problem with the smelling or texture of the fluids is that they were mixed in the bleeding process in the syringes themselves so its hard to say if they smell different or even look different. I just know that there are oil globules mixed in the fluid... as in they are not mixing together. I have not seen any leaks and the shop changed it initially about a month, maybe month and a half ago, and I just did the second bleed 2 days ago and haven't ridden since. They brakes seem to be more responsive and braking with a lot less pull, which is a good sign, but again, haven't been on an actual ride since the switch. I've attached a picture of the fluid out of the syringe... its a little hard to see because its in a glass jar, but you can see the oil globules in it. As for the levers hardening, they did not after a few pumps, but again, they are better after the second bleed. I just was getting very little braking until further into the pull. The reach could have been a contributing factor, but when I bought the bike the brakes were responsive and the reach was the same.
 

Attachments

Location
Loch side.
Thanks everyone for the replies. Im sure that its not air bubbles. I kept the fluid and its definitely still separated. When I bled the brakes I had a syringe attached at top and bottom and pushed fluid from top syringe into the bottom...old fluid being pushed out, new fluid coming in. The old fluid did not appear pink, but at points it had a black tinge to it (I've been told this is normal with older brake fluid coming out). The problem with the smelling or texture of the fluids is that they were mixed in the bleeding process in the syringes themselves so its hard to say if they smell different or even look different. I just know that there are oil globules mixed in the fluid... as in they are not mixing together. I have not seen any leaks and the shop changed it initially about a month, maybe month and a half ago, and I just did the second bleed 2 days ago and haven't ridden since. They brakes seem to be more responsive and braking with a lot less pull, which is a good sign, but again, haven't been on an actual ride since the switch. I've attached a picture of the fluid out of the syringe... its a little hard to see because its in a glass jar, but you can see the oil globules in it. As for the levers hardening, they did not after a few pumps, but again, they are better after the second bleed. I just was getting very little braking until further into the pull. The reach could have been a contributing factor, but when I bought the bike the brakes were responsive and the reach was the same.
No matter how I turn my head or what I smoke, I cannot figure out what's going on in that photo.
 
OP
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ryckee

New Member
Lol, sorry. The fluid is in a jar so its a little difficult to see. Is this any help at all??
 

Attachments

fossyant

Ride It Like You Stole It!
Location
South Manchester
Buy a 1 litre bottle of 5.1 from a car shop and keep bleeding them to get the air and any contamination out. Its far cheaper than Rock Shox labeled stuff.

PS did your jar have any other fluids in before. I just use the same jar for spent fluids, be it brake oil, dot fluid or transmission oil (used in my dropper).
 
OP
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ryckee

New Member
Thanks fossyant, I didn't have any other fluid in the jar prior, it was clean and dry. The brakes seemed to be working really well after I bled them again, but then I adjusted my reach and again they seem unresponsive. So maybe it is a reach thing??? I tried putting the levers back to where they were and it didn't change the responsiveness, they just suck again. Or maybe air is getting in there when I adjust the reach? I measured the reach to what was recommended when I bled the brakes, but maybe since I have smaller hands I need them adjusted differently when I do the bleed process. Anyone have any thoughts on that?
 

Levo-Lon

Guru
You could try putting the lever under load, and zipp tie it, then leave it for a day.
This usually clears any problematic air.

Are your calipers clean, as this could also be sticky seals, so after brakes applied the pads pull back more due to the pistons being stuck to the seals, hence excessive lever traval.
Any signs of fluid passing the pistons? Could be a sign of caliper leak.

If your happy with the fluid now, id be looking at my above points
 
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