Well thats 1/2 day I'll never get back, but at least my brakes now have DOT5 in them instead of DOT4....
Bike is fitted with JayBrake bar, foot brake and both calipers and they say they will run with both DOT4 and 5, but the DOT4 fitted was leaching out of the reservoirs around the joint line and making a mess.. also, I'd had both front and back plastic bobbins in the cylinders expand in the sun and lock on at differant times so thought I'd get the DOT4 out..
DOT5 is a lot nicer to work with as it won't get your paint and it does feal more like a lubricant than the DOT4
So both the bar and to foot piston have been taken in bits and cleaned out, both lines purged, and both calipers taken in bits, seals out and cleaned... not a trace of DOT4 left...
Re-filled and bleed with the new stuff... if it stops raining sometime this month, I'll give her a go before the layup for winter :) :chop:
If DOT 5 is silicone ...
Silicone brake fluid will never give you that hard feeling.
Seriously.
It always will feel mushy hince you will not ever find it in use on a race track.
Carry on do as you wish.
"Silicone brake fluid will never give you that hard feeling."
Total BS, with braided lines DOT 5 gives a very hard positive feel. If your lines are old wore out rubber replace them, no matter what fluid your using.
Do as you wish.
As I said you will not ever find silicone at the track.
Not being contentious...just the facts.
Race track? Really? Any of you guys got your bikes on a race track? I mean more than a 1/4 mile long? The reason they don't use DOT5 on ROAD COURSE race tracks is due to the temperature rating. Actual road coarse race bikes are on the brakes HARD, and FREQUENT. The brake rotors get RED HOT. Tends to boil the brake fluid, especially DOT 5. Unless you plan on riding such that you're turning your brake rotors red hot, don't worry about DOT 5.
DOT 5 is the best choice for street bikes. Especially ones that you care about the painted surfaces. Which I'm assuming 99.9% of the dudes reading this crap have.
-JW
The other problem with DOT 5 is it can be very hard to bleed at times.
None of our competing Porche teams used it.
If nothing else it is a good education here.
Of course, Dot 5 will not harm your paint .
But it does suck H20 out of the air faster than its counterpart.
Carry on.
"DOT 5 is the best choice for street bikes"
:up: I agree, been using it for over 30 years, and never had a hard time bleeding.
I run DOT 5 in my FXR, my 2015 RG has DOT 4, the photo shows what it does when the gasket weeps a little. And the lever isn't any firmer than the bike with DOT5.
I also haven't noticed that DOT 5 is noticeably harder to bleed than DOT 4. Harley four puck calipers are a pain to get all the air out of, though!
One thing about DOT 5 that is true, is that tends to get micro-bubbles over time. Which is why they don't use it in anti-lock brake systems, the pulsing of the ABS can foam up DOT 5. And also why you need to bleed the brakes more often with DOT 5 than DOT 4. My usually drill is to bleed the caliper at every tire change or brake pad change.
-JW
Quote from: Deye76 on October 27, 2019, 07:07:49 AM
"DOT 5 is the best choice for street bikes"
:up: I agree, been using it for over 30 years, and never had a hard time bleeding.
I run DOT 5 in my FXR, my 2015 RG has DOT 4, the photo shows what it does when the gasket weeps a little. And the lever isn't any firmer than the bike with DOT5.
Silicone does not absorbe water... DOT4 does... thats why you have to change it....
https://lifeatlean.com/motorcycle-brake-fluid-guide/
DOT 4 vs DOT 5.1
DOT 5.1 is more hygroscopic than DOT 4 so it absorbs more moisture. Because of this it needs to be changed more often
Other people say it is its very big problem.
carry on.
DOT 5.1 is not DOT 5
silly little dismal point anyway.
DOT 5 is silicon based and 5.1 is glycol based. Both have the same boiling point which is higher than DOT 3 & 4.
I find that when I bleed my brakes, I now am using the practice of tying down the brake handle and pedal overnight to rid the system of bubbles and sponginess. I don't always have problems with it, but just do it now as standard procedure to avoid problems. It seems to firm up everything up slightly more than not doing it.
Quote from: thumper 823 on October 27, 2019, 12:33:51 PM
silly little dismal point anyway.
You're the one that seems to be confusing them. The thread was about 4 vs 5 until you brought up 5.1 :unsure:
Quote from: thumper 823 on October 26, 2019, 08:17:35 PM
The other problem with DOT 5 is it can be very hard to bleed at times.
None of our competing Porche teams used it.
If nothing else it is a good education here.
Of course, Dot 5 will not harm your paint .
But it does suck H20 out of the air faster than its counterpart.
Carry on.
DOT 5 does NOT absorb water. :doh:
Hoss :up:
IMO leaving the brake systems under pressure for 8,10, 12 hrs ..... overnight, allows the microscopic air bubbles in the DOT5 to slowly rise in the lines, when they bump into one another they will become one, eventually there will be perhaps only a few bubbles at the top of the lines and will bleed out when the levers are slowly released
I've never really had any problems bleeding brakes regardless of the fluid used and my 03 Fatty has Dual HD Brembos with DOT5.
One of my brothers that has an EVO Softail Custom has nothing but trouble, I've shown him how I bleed brakes but he has his own method and consequentially his own results.
I use DOT5 so as to avoid any problems with paint damage and moisture degrading the brake system, if it weren't for that I'd be using Toyota DOT3.
I see lots of different "opinions" here. Here's a link that I expect is fairly accurate that should clear up the debate.
.https://help.summitracing.com/app/answers/detail/a_id/414/~/what-is-the-difference-between-brake-fluids%3F
Thats right and the reason to use dot5... With dot4 i found the water absorbed in it was turning the Ali in the capliers a bit and in one piston induced a leak due to oxide build up under the seal. Use Dot5 and it won't do that as it won't draw water in (unless it finds another way in there)
With the JayBrakes its imposable to blead in the traditional way or so I've found, but tilt the bike so there are no trap points, the air comes up to the top and comes out in bubbles until its all clear.. takes about 30 mins to do but a lot simpler process than pumping and opening nipples
Feals just the same as the Dot4...
"I've never really had any problems bleeding brakes regardless of the fluid used and my 03 Fatty has Dual HD Brembos with DOT5."
:up: My FXR has dual front late model Brembo calipers with DOT 5, also, and I also don't have a problem bleeding brakes, with whatever fluid. Years ago I used a pump oil can with a hose that went over the bleeder nipple, and back bled 'em. Now I use a hand operated Mighty Vac, piece of cake.
A little more definitive
https://www.brakeandfrontend.com/brake-fluid-dot-3-4-5-5-1-faq/
Quote from: thumper 823 on October 27, 2019, 07:01:22 PM
A little more definitive
https://www.brakeandfrontend.com/brake-fluid-dot-3-4-5-5-1-faq/
all credibility went out the window when he said "
safe for breast implants"
Quote from: FSG on October 27, 2019, 07:44:36 PM
Quote from: thumper 823 on October 27, 2019, 07:01:22 PM
A little more definitive
https://www.brakeandfrontend.com/brake-fluid-dot-3-4-5-5-1-faq/
all credibility went out the window when he said "safe for breast implants"
Hmmm, that kinda crossed my mind too. :scratch:
Quote from: FSG on October 27, 2019, 07:44:36 PM
Quote from: thumper 823 on October 27, 2019, 07:01:22 PM
A little more definitive
https://www.brakeandfrontend.com/brake-fluid-dot-3-4-5-5-1-faq/
all credibility went out the window when he said "safe for breast implants"
:hyst:
Quote from: Hossamania on October 27, 2019, 12:59:42 PM
I find that when I bleed my brakes, I now am using the practice of tying down the brake handle and pedal overnight to rid the system of bubbles and sponginess. I don't always have problems with it, but just do it now as standard procedure to avoid problems. It seems to firm up everything up slightly more than not doing it.
I do the same. I don't understand the physics behind it, but it works like magic.
Jason
Tying down the brake lever puts a "shape memory" into the rubber seals and will give you a firmer feel until the rubber relaxes.
It goes not facilitate air bubble egress.
The best way to clear any bubbles is to back bleed, you can do this (after bleeding the caliper) without opening a bleeder by pushing the pistons all the way back into the caliper.
This will move fluid into the reservoir and any air will separate there.
After letting it sit for that to happen slowly pump the lever to push the pistons back out to take up the slack.
The best tool for bleeding brakes is patience. If your fluid gets foamy just stop and wait a half hour or so and the bubbles will coalesce and bleed easy. Don't get rowdy jacking off the brake lever in your final bleeding steps, this can break up the larger bubbles. Also park the bike with the bars oriented so any bubbles will rise to the relief hole in the master. You can usually get this by having the bike on the side stand and turn the bars full to the left. With some bars you may have to block up the front tire a bit to get the lean angle high enough to do this.
I don't care for vacuum bleeders as they can create bubbles. The fluid can cavitate under vacuum conditions, and the final bleed needs to be done by hand anyway.
Another thing that can catch bubbles is a rise in a brake line, bubbles will not migrate down hill, they have to be pushed by enough flow to carry them past the high point. You can raise the front of the bike to make the line all down hill from the master and let it set like that and the bubbles will migrate to the master where they can be burped out by tickling the lever before taking the bike down. Let Gravity do work for you if the bleeder is well below the reservoir, fluid will naturally flow out the bleeder (not fast but it will move, and not make foam).
Every setup is different, try bleeding the front master on some rabbit bars! I had to remove the front master and suspend it with a cord from above (oriented so everything was down hill from the relief hole).
All I can tell you is that I've bled brakes many times, and occasionally I just cannot get the handle to firm up. This on the same bike that I've not had problems before. Tying it down overnight solves the problem.
Quote from: Hossamania on November 12, 2019, 12:15:35 PM
All I can tell you is that I've bled brakes many times, and occasionally I just cannot get the handle to firm up. This on the same bike that I've not had problems before. Tying it down overnight solves the problem.
Indeed it does. :agree:
If after a reasonable amount of bleeding I find that the brake is still a bit mushy I don't waste any more time or brake fluid trying to get the remaining air out. Instead I tie the lever down and leave it over night. The next day after removing the strap/bungee and pumping the brakes a few times, the brakes will be as firm as they can possible be.
This method works well and is permanent. I've successfully performed this technique on not only HDs, but Japanese and British bikes.
Jason
Quote from: Norton Commando on November 13, 2019, 05:36:27 AM
Quote from: Hossamania on November 12, 2019, 12:15:35 PM
All I can tell you is that I've bled brakes many times, and occasionally I just cannot get the handle to firm up. This on the same bike that I've not had problems before. Tying it down overnight solves the problem.
Indeed it does. :agree:
If after a reasonable amount of bleeding I find that the brake is still a bit mushy I don't waste any more time or brake fluid trying to get the remaining air out. Instead I tie the lever down and leave it over night. The next day after removing the strap/bungee and pumping the brakes a few times, the brakes will be as firm as they can possible be.
This method works well and is permanent. I've successfully performed this technique on not only HDs, but Japanese and British bikes.
Jason
The ONLY way I have been able to get a firm "peddle" on the front of my FLH