Major Rear Brake Problems
Thread Starter
|
Advanced
Joined: Jun 2009
Posts: 82
Likes: 0
Major Rear Brake Problems
So I changed the rear pads on my 97 EG. My caliper froze up so I had to take it off and get it fixed. After I got that all fixed up I installed it and now have to bleed my rear brakes. I went to the dealer and asked for some brake fluid for my rear brakes. He gave me a bottle and I was on my way. I put some of the fluid in the res. and started pumping the pedal. It would slowly gain pressure, then I would hold and bleed. I did this for a while and noticed my fluid started coming out muddy. I thought nothing of it(big mistake). I was really getting no progress, it would get a little tension and then I would bleed and get muddy fluid. I THEN decided to look on top of the res. cap and it says to use DOT 5 only. Well the parts guy and the dealer gave me DOT 4. I already put in half a bottle. So I took all the fluid out of the res. and pressed the pedal a few times to get all the fluid out of the lines(I think I got it all out). Now I am going to get the DOT 5 and start over. My question is...is there a better way to do this than to just fill the res. and start pumping the pedal? That seems to take quite a while, especially with no fluid in to start with. Any help will be appreciated. Sorry for the long sob story.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I recently did a rear brake bleed (new caliper and hose) and the thing almost bled itself! On my bike the reservoir is under the left side cover, so has a good head above the caliper. There are various tools you can buy to pressure the system, but go to the DIY forum and read through the brake bleeding tips there first. Best of luck! It was my front brakes that gave me problems last time I did this.
Stellar HDF Member
Joined: Mar 2007
Posts: 2,034
Likes: 45
From: Michigan
Found this on the net.. Very interesting
Silicone Brake Fluids
In years past, all brake fluids were glycol. Then D.O.T. 5, a silicone fluid having a higher temperature rating, emerged, initially to meet the higher boiling point requirements of racing use. (Race car brake systems include oil-cooler-like heat exchangers and ceramic pads.) Silicone fluid was able to withstand the most heat of any brake fluid, so it earned a reputation as a racing brake fluid. However, silicone brake fluid has properties very different from glycol fluid, and has its own pros and cons. On the advantage side, silicone fluid will not harm paint or plastic, and does not aggressively attract additional moisture as glycol fluid does. On the disadvantage side however, silicone fluid aerates easily. Harley-Davison, one of the sole current OEM users of silicone fluid, warns buyers to let the fluid sit at least an hour before using it. The trip home in the saddlebag is enough to aerate silicone brake fluid until it looks like a freshly poured soft drink. Silicone fluid is also slightly more compressible than glycol fluid, does not change color to tip the user to its moisture content, and worst of all, neither accepts or disperses moisture, making systems using it more corrosion prone, and requiring much more frequent fluid changes. Silicone brake fluid also lacks glycol fluid's naturally occuring lubricity, making it incompatible with the mechanical valving in some antilock braking systems.
Silicone Brake Fluids
In years past, all brake fluids were glycol. Then D.O.T. 5, a silicone fluid having a higher temperature rating, emerged, initially to meet the higher boiling point requirements of racing use. (Race car brake systems include oil-cooler-like heat exchangers and ceramic pads.) Silicone fluid was able to withstand the most heat of any brake fluid, so it earned a reputation as a racing brake fluid. However, silicone brake fluid has properties very different from glycol fluid, and has its own pros and cons. On the advantage side, silicone fluid will not harm paint or plastic, and does not aggressively attract additional moisture as glycol fluid does. On the disadvantage side however, silicone fluid aerates easily. Harley-Davison, one of the sole current OEM users of silicone fluid, warns buyers to let the fluid sit at least an hour before using it. The trip home in the saddlebag is enough to aerate silicone brake fluid until it looks like a freshly poured soft drink. Silicone fluid is also slightly more compressible than glycol fluid, does not change color to tip the user to its moisture content, and worst of all, neither accepts or disperses moisture, making systems using it more corrosion prone, and requiring much more frequent fluid changes. Silicone brake fluid also lacks glycol fluid's naturally occuring lubricity, making it incompatible with the mechanical valving in some antilock braking systems.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
Silicone fluid is also slightly more compressible than glycol fluid, does not change color to tip the user to its moisture content, and worst of all, neither accepts or disperses moisture, making systems using it more corrosion prone, and requiring much more frequent fluid changes.
Interesting stuff. I have been using DOT5 for twenty years now and have used mostly HD's own. It is a blue/mauve colour when new and I can assure readers it does discolour over time, to a pale gold colour. Why it does that or what causes it I have no idea, but it takes no more than two years in my experience. So I change mine at 2-yearly intervals, which is good practice, whatever fluid is used.
Having previously owned a Harley that used DOT3 fluid, I can also confirm that stuff deteriorated in barely a year, from clear to a dirty brown colour. So DOT5 has a much better service life IMHO! After discovering how disgusting the stuff got I changed fluids on that bike every year.
Thread
Thread Starter
Forum
Replies
Last Post
