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Lotus Elan Central
Bleeding Brakes

This procedure runs through bleeding the brakes on your Elan. This material contained on this page is informational in nature only, and does not imply all knowledge needed to safely work on the braking system of your Elan! I will not warranty the contents nor will Lotus Elan Central take responsibility for your actions if you should attempt to work on your Elan's brakes based solely on these instructions

When to Bleed your Brakes:

Because DOT 3 & DOT 4 fluid is glycol based, it absorbs moisture over time. Moisture seeps in through microscopic pores in the rubbers seals and hoses. It enters every time someone opens the master cylinder reservoir to check the fluid level. Most fluid reservoirs are transparent so the level can be checked without having to open the lid. Brake fluid is so hygroscopic (attracts water) that leaving the lid off fresh brake fluid can ruin it overnight--it will absorb so much water from the air it will be too contaminated to use.

Moisture contaminates the fluid causing a drop in its boiling point which leads to fluid boil and brake fade during hard use. Moisture causes internal corrosion in the calipers, wheel cylinders, and steel lines. The reason for replacing the fluid periodically is to get rid of the contaminated fluid and to restore the heat and corrosion resistance of the fluid.

When a car's brake fluid is one year old, it contains 2.5% water. At 18 months, the water moves up to 3% which is enough to lower the boiling point of the fluid by 25%. After a few years, fluid can have 7% to 8% water. Many experts recommend changing brake fluid at two years or 24,000 miles. At the very least flush the brake fluid completely at every brake job.

You SHOULD bleed your system and change your fluid at least once a year to get the moisture laden old fluid out. Your brake system will last much longer this way as the moisture in old fluid causes corrosion of the brake systems internal parts. If you are racing or using the car for hard driving and braking, the fluid changes should be much more frequent than that.

Fluid Fade:

Fluid fade usually has a gradual onset--the phenomena is started by the boiling of the brake fluid in the calipers. This produces bubbles in the brake system. Since bubbles are compressible, this makes for a soft, spongy pedal. In worse cases, the pedal can plunge to the floor with very little slowing! Fluid fade can be avoided by running a high grade racing-type brake fluid and/or frequent changes of brake fluid. Also if you change the pads before they get super thin, the thicker pad friction material will help insulate the calipers from the heat.

Bleed versus Flush:

There are really two different things to do with brake fluid: bleed and flush. Bleed is where you replace a little of the fluid. This may be done after a brake pad change or after boiling the fluid in the calipers. Flushing the system is where you replace all the fluid in the system. This would be done on a yearly or bi-yearly basis or after major brake system work. Both bleeding and flushing the system are often referred to as "bleeding" because the valve on the caliper is called a "bleed valve." What will be called "bleeding" in this write-up is technically a "flushing"!!


Parts Needed:
Brake fluid (see discussion above)
Brake cleaner spray

Tools Needed:
Protective gloves
Jack and jack stands
Wheel lug wrench
Torque wrench (recommended and worth buying!)
Bleed Screw wrenches (9mm AND 10mm)
"turkey baster" (read on!)
clear vinyl hose, about 30 cm. (auto or hardware store)
catch bottle (empty, screw-top soda bottle)
(you can get a "bleed kit" with the tubing and catch bottle at the auto store)
flashlight or work light
small rubber mallet


Before you start: Brake fluid is hydroscopic which means it has an affinity to water and absorbs water from the air. When brake fluid absorbs water it’s boiling point drops rapidly. That why it is important to use only very fresh brake fluid, preferably from a recently opened bottle where the factory seal has just been broken. When bleeding brakes, keep the bottle capped except when you are pouring the fluid out. It is also a good practice to keep the cap of the master cylinder reservoir on, but only loosely screwed about ½ turn while you are bleeding, as the brake fluid pulls in the humidity from the air and thus you want to minimize its direct exposure to the air. Only use brake fluid that hasn't been previously opened.

Bleed one wheel's caliper at a time, doing them in order of decreasing brake line length. This means:

rear right, rear left, front right, front left.

Bleed Procedure: (Stroke Method) This method is traditionally a two-person job.

  • Open the hood. Clean around the cap of the brake fluid reservoir, but do not use water now (remember water is your enemy here!). Remove the cap, then remove, by sucking out (you should buy a $3 turkey baster) all the fluid in the reservoir until you can see the intake opening at the bottom of the reservoir--use flashlight if needed. Leave just enough fluid to cover the holes. Then slowly, as not to mix the fluids more than necessary, fill the reservoir with new fluid to the very top.
  • Go to the first wheel caliper you plan to bleed. Take tools, paper towels, brake cleaner spray, and the work light.
    Loosen the wheel lug nuts just a bit!
  • Jack this corner of the car up enough to remove the wheel. Be careful not to scrape the front of the wheel as you set it aside.
  • Ah-ha, there's that famous Lotus suspension again. Now is your time to inspect the current condition of your suspension parts, bushings, brake lines, calipers, rotors, brake pads, etc. Be sure you do not need to replace the brake pads before this brake bleed! (see front brake info)
  • Remove the plastic dust cap from the bleed valve on the caliper (do not lose it).
  • Place the correct wrench over the valve--the rear screw is 10mm and the front screw is 9mm. Then push the vinyl hose over the valve, capturing the wrench. Put the other end of the hose into your catch bottle. You may want to make a circle/loop with the tubing so air cannot rise within it!
  • Gently tap the caliper with the rubber mallet to help the air bubbles rise to the bleed nipple--repeat as needed.
  • Get your accomplice (#2) into the driver's seat, with his/her foot on the brake. #2's job is going to be pumping the pedal, to force fresh fluid from the reservoir out to and out of the caliper.
  • Be sure to add the NEW brake fluid to fill the reservoir full prior to beginning the bleed at each corner!!
  • Have your friend apply pressure to the pedal. You (#1) crack the valve on the caliper, about 1/4 to 1/2 turn, and let fluid drain into the catch bottle. When #2's foot has pushed the pedal partway down, s/he signal's #1, who then closes the valve lightly.
  • Do NOT push the pedal to the floor--this can cause damage to the seals of the master cylinder. You should only push the pedal as far as the normal travel. You can place a piece of wood, your other foot, or other hard item behind the brake pedal to assure you do not depress it too far.
  • Important!! #2 should NOT release the brake pedal until #1 has closed the valve. Otherwise, the rising pedal will suck air back into the caliper (BAD!!).
  • The two of you need to establish a coordinated rhythm. Something like:
#1 (in driver's seat) #2 (at caliper)
applies pedal pressure,  
says: "Pressure!"  
  opens valve
  says: "Open!"
pushes pedal down,  
then says: "Down!"  
  closes valve
  then says "Closed!"
releases pedal,  
says: "Releasing...Up!"  

You need to repeat this cycle a number of times. Look through the vinyl hose, watching the quality of the fluid coming out the valve

  • If you're flushing the fluid, the number of pumps needed depends on the line length. Look for fresh, clean fluid coming down the hose. If you're replacing standard brake fluid with ATE Super Blue, it'll change colors--> a-ha, the reason to get it! From golden (or brown), it'll turn green, and eventually blue. Keep bleeding until it's a nice Smurf blue
  • In all cases, watch your fluid level in the reservoir. Do NOT let it fall more than half-way down! If the reservoir runs dry, you will suck air into the lines and have to start all over. Watching the reservoir and keeping it filled is a possible job for a third person
  • When you're done with a valve, close it snuggly, remove the hose and wrench, and replace the dust cap. Wipe up any fluid which has dripped and clean the area with the brake cleaner spray. Brake fluid will remove paint if left alone, so be sure to clean properly!! Replace the wheel and move the jack to the next corner
  • And when you're done all 'round, check the pedal feel. If you have any doubt about the work you've done, don't drive the car. Get help!
  • Top off the brake fluid reservoir to the "Max" mark, replace the cap, and wipe up any spilled fluid

Bleeding using a Hand Vacuum Pump: (Vacuum Method)

You may want to invest in a simple vacuum pump to bleed the brakes. One such tool, (supposedly??) available for about $20 at Walmart is the "Mityvac Vacuum Pump / Brake Bleeding Kit." The pump is applied to a bleed nipple, and pulls fluid through the system. This technique has the advantage that it is a one-person job! I have not seen this product or heard from anyone that has actually used it so can give no feedback about it.

Griot's Garage sells (among other neat things) a neat little vacuum extractor for $65. This is what I use! It has a brake bleed valve end-attachment. ITEM#10122, phone 800-345-5789.

Similar method here except you can do it by yourself and save all that pizza and beer money and payback-favor-time needed for your helpers!

In brief: connect hose to bleed valve, build small pressure in line (one pump of handle), crack valve open, observe slow fluid flow out, be patient, wait more, hang in there, observe the fluid change colors, close the bleed valve, remove the hose, clean up, and get on to the next caliper!!

Important: Do not build a high pressure using a vacuum method. This can cause cavitations within the fluid and/or can cause air to be drawn in thru the bleed screw threads!

HINT: I found it best to fully remove the bleed screw, put a single turn of white thread-seal tape around the screw threads, and then re-install. This assures an air-tight seal for use with the vacuum method.


DIAGNOSING BLEEDING PROBLEMS:

No air or fluid will come out the opened bleeder screw
A. Bleeder screw plugged
B. Brake line, hose or valve damage
C. Air leaking in through bleed screw
D. Master cylinder outlet plugged

Low or spongy pedal after bleeding
A. Air in the system
B. Mechanically related

Speedbleeders:
I am working on finding the proper Speedbleeders for the Elan!
Check out their web site at http://www.speedbleeder.com/

These are pretty cool and are getting rave reviews from all the magazines and auto web sites. They eliminate time consuming and messy brake bleeding and make it a one-person job! Simply install, loosen 1/2 turn, slowly step on the brakes about 4-5 times, tighten and you're done! This valve bleeds the brakes without allowing air back into the system using a spring check valve! Simple and Ingenious! COST and TIME EFFECTIVE!

Cost should be about $6.50 each.

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