Saturday, Mar 01, 2008 at 12:41
his is how I was taught when I did my apprecticeship & it has served me
well for 40 years. I have never repaced or re-sealed a wheel cylinder, caliper or m/cyl on any vehicle I have owned & none has ever leaked and most were kept for many years. If you don't have pressure bleeding equipment do the following:
1. Siphon all fluid from the m/cyl using a clear length of beverage tubing or G-J clear tubing with an internal dia that fits snugly over your brake bleeder nipples. Suck the remaining fluid out from any depressions (you can see it coming up the tube so you dont get a mouth full) I use an ice cream container to contain all the old fluid and place it close to the m/cyl so you are not dripping fluid on the paintwork. If you do spill any wash with running H2O immediately. Get any black gunge remaining in the m/cyl out with clean lint free rag and wrapped around a small screwdriver.
2. Re-fill the m/cyl using clean new fluid (per the specs in your handbook) & re-fit the cap. Make sure you new fluid is not past its shelf life because stored in the shed "for years" it can absorb moisture, especially once the container has been opened, and defeats the purpose of what you are trying to achieve. The higher the DOT # the higher the boiling point. Brake fluid is very hygroscopic which means it suck moisture from the atmosphere & can absorb its own weightin H2O.Any moisture in the fluid lowers the boiling point & the fluid gets very hot when braking hard & if it were to boil gas bubbles are produced which being compressible = pedal to the metal & no brakes. Not good!
3.First go to the wheel furtherest away from the m/cyl (this is important) & using the correct size ring spanner gently check if the bleeder will turn anti-clockwise slightly but not enough to open it letting air into the system. Once you know it is able to be undone fit the clear tube over the bleeder nipple. If you have the correct size it will be tight fit & if necessary heat it first in hot water. Using the correct tight fitting ring spanner is important as the bleeders can be very tight & round off easily & break off as
well if you force them too much.When you first
test each one for tightness watch the bleeder as the spanner turns & if you see any hint of the spanner turning & the bleeder on the wheel side of the spanner staying stationary STOP because it is going to break off. They get seized easilyas they seal on a machined taper
seat.
4. Place the tube in a small jar & have someone hold their foot firmly on the brake pedal. Open the bleeder until the pedal has reached the floor. Close the bleeder & tell them to let the pedal up & pump it until firm again. It is important not to let any air into the system so DO NOT have the bleeder open at any time the pedal is not under pressure or held down to the floor. Repeat the pedal pumping & bleeding until clean fluid comes the the clear tube. DO NOT let the m/cyl level get too low. If you do air gets in the system & is a bugger to get all of it out
5. Repeat this process at each wheel in order of distance from the m/cyldoing the one closest to the m/cyl last. Make sure all bleeders are tightened firmly & their rubber dirt caps are re-fitted.
6. Wash off any spilt lfuid with water, degreaser is not needed.Make sure the m/cyl is topped up. Regards pushing the m/cyl piston & seals past their polished zone into a pitted zone, the whole m/cyl
bore is polished from new & if the fluid is flushed regularly (at least evey 24 months) there wont be a pitted zone. You will be amazed at the #rap that comes out in the old fluid & if bad enough you may experience slightly more responsive brakes. Good luck.
AnswerID:
290230
Follow Up By: Gerhardp1 - Saturday, Mar 01, 2008 at 15:42
Saturday, Mar 01, 2008 at 15:42
The Supercheap non-return valve allows you do do all this with one person, not two.
FollowupID:
555570