Draining brake fluid


#1

Vehicle: 1996 Dodge RAM 2500



Symptom: Squishy brake pedal sensation and only acceptable but not excellent stopping power.



My diagnosis: Air in brake lines.



Treatment: Drain air out of brake lines using pedal pumping technique from Chilton manual with assistant.



Service already performed: My attempt to get air out of the brake lines ended in only moderate success. It turns out that I needed a smaller and more flexible hose to attach to the bleeder screws, which should be easy to remedy. However, I ran into other problems that have me stumped.



Question 1: The bleeder screws were very hard to turn, especially with the flexible hose attached to the nozzle on top of the screws. I tried a ratchet to loosen them initially and then needle nose pliers to loosen/tighten them during the pedal pumping process. Even the ratchet could not loosen one of the bleeder screws. Which tool should I use for this task?



Question 2: A friend recommended spraying the screws with WD-40 to loosen them in advance. Is that a good idea?



Question 3: The brake fluid in my reservoir was very dark colored and smelled foul compared to the nearly clear and relatively odorless fluid I was using to top up the reservoir. The manual says to use DOT-3 and that’s what I bought. What should I do about this?



Thanks so much, cartalk superheroes! I’m still relatively inexperienced when it comes to cars, so if I can pay any of you back with some free computer help (my area of expertise), please let me know.


#2
  1. Don’t! use needle nose pliers or anything but a high quality wrench of the correct size to turn the bleeder screws. If you stop at a parts store you can buy wrenches that are meant for brake bleeding. I just use a normal box end. And use the right size - metric if yours are metric /standard if standard. (They are likely either 8 or 10mm). Loosening first with a 6-sided socket is a good idea - then snug it back down, put a box end wrench on it, then attach the bleeder tube. Open and close with the box end wrench - it only takes a wee little turn - 1/8-1/4 or so.

  2. Rather than WD-40 use PB-Blaster. And yes it is a good idea. Soak a few times and see the note above about using a 6 sided ratchet to loosen it.

  3. This means that its been way too long since your brake fluid was flushed out and refreshed. Get some kind of a little hand pump or turkey baster type sucker. Suck out all of the fluid in the reservoir. Refill with fresh brake fluid of the recommended kind. Now proceed to bleed the brakes, but hang at each wheel until the fluid that comes out is clean. MAKE SURE that you check the fluid level a lot as you go along - if it runs dry you’ll be sucking in more air.


#3

my particular techniques i employ:

using the correct size socket over the bleeder screw. metric or standard, six point ONLY.

once it is loose, six point closed wrenches (so i don’t strip or round the bleeder screws)

when bleeding the fitting, only open 1/4 turn. more lets too much air flow around threads. leave the wrench on the hex while the hose is on, so the hose can be turned with the bleeder screw. (don’t use pliers or vise grips, you are only setting yourself up for a HUGE problem next time (rounding off even a little bit is bad))

rather than the two man scenario, the bottle, with vent, and the inlet hose is submerged in fluid in the bottle is more practical, and efficient.

make sure, ABSOLUTELY sure, you never drain the brake fluid reservoir. big hassle. keep it filled up during the brake bleeding process.

correct order, right rear, left rear, front right, front left.

bleed until no bubbles emerge.

you got the process? apply pressure, helper cracks screw, you pump all way down, at bottom holler to helper, tighten screw, then let up on pedal, repeat until clear. all the while make sure you never let the reservoir go dry.

and IF you strip (or partly strip) a bleeder screw, buy a new one. once they get a little rust, and have a slight round on them, they are a #$%^& to remove.


#4

correct order, right rear, left rear, front right, front left.

Check your manual on that one since it might be RR - LF - LR - RF. On the diagonals rather than back to front.