Hi,

         I need to replace the brake fluid on my '96 850 Turbo Wagon. Based on the positive reviews, I've
         ordered a Power Bleeder so I can pressure bleed the system. I'll be using ATE Super Blue fluid, which
         has worked well in my Porsche.

         I'd appreciate some advice on the preferred technique to replace the brake fluid, as there are some
         significant differences between the Haynes and Volvo shop manuals.

         The Haynes manual indicates that fluid replacement is not anything more complicated than an extended
         bleed procedure (i.e., just running all the old fluid through while bleeding). They recommend doing both
         of the rear calipers first (order not important), and then right front and finally left front. Since I have the
         UK Haynes manual but have a left hand drive car, I assume the front sequence should be inverted for
         me. The Haynes procedure is essentially what I'm used to on the Porsche.

         However, just to cross reference I checked my Volvo shop manual for brake fluid replacement. There
         are two major differences versus Haynes. Volvo suggests the inverse order of wheels (e.g., start with the
         left front, then proceed to the right front, left rear, and right rear calipers). As well, for fluid replacement
         Volvo also recommends pushing the brake pistons in all the way (presumably to push out all the fluid,
         although I would have assumed that the pressure bleeder would have been sufficient for that purpose).

         What have people found to be the best procedure?

         Thanks in advance,

         Garth

... posted by Ray Niblett  on Wednesday, 7 March 2001, at 6:39 p.m. ...in response to "850
         brake fluid replacement procedure" posted by Garth Gullekson.
 

         Garth, I have the same power bleeder and can't answer any
         of your questions. Instead, I want to add a couple more:

         How much pressure should be used in the power bleeder?
         Directions say about 10 PSI but check your car's repair
         manual for specifics (a manual which I don't have).

         How much fluid did it take to do the whole job?

         I have a manual tranny. I assume it shares the fluid with
         the brake (for clutch operation). Anything to be aware of
         here?

         As far as pushing in the brake pedal: I have seen posts here
         that say that can cause a problem with some of the seals and
         you should not press the brake pedal down too far when bleeding.
         I don't plan on touching the brake pedal if I can avoid it when
         flushing brake fluid.

         --
         Ray Niblett 95 855 GLT / 98 S70 T5M

... posted by Garth Gullekson  on Wednesday, 7 March 2001, at 8:38 p.m. ...in response to "Re:
         850 brake fluid replacement procedure" posted by Ray Niblett.
 

         Ray,

         I haven't done the brake fluid replacement yet (hence my posting), but I'll try to answer your questions
         as best I can from the manuals and general experience rather than actual experience on the 850.
         Hopefully some of the Volvo dealer techs on this board will answer both of our questions more
         competently than I can attempt to!

         According to the Volvo Brake manual (850 1996 onwards, TP 5002202) in the section on "Brake
         Fluid, replacement with bleeding unit" they recommend setting the pressure bleeder to a range from 29
         psi to 42.7 psi. However, they also say you should follow the bleeder's manufacturer's instructions for
         connecting and using the bleeder. I don't know if that is a higher pressure range than what the Power
         Bleeder recommends. The shop manual does note that bleeding brake systems with ABS takes longer
         than bleeding conventional brake systems, and maybe that's why relatively high pressures are
         recommended to speed up the process.

         As to the amount of fluid required for a complete replacement, here are two partially conflicting data
         points. My owner's manual indicates a capacity of .6 liters. Tbe Volvo shop manual doesn't list any total
         capacity, but does indicate when replacing fluid to pull .2 - .3 liters out from each caliper, which would
         suggest you need .8 - 1.2 liters to do all four wheels. The shop manual doesn't mention a technique that
         many people use, namely to pull out fluid from the master cylinder (with an absolutely clean turkey
         baster or whatever, don't borrow your wife's kitchen gadget for this one!) and then fill the master
         cylinder with clean fluid before starting the process. That approach should reduce the amount of fluid
         that has to be pulled from each wheel before you hit clean new fluid.

         There wasn't anything in the brake manual highlighting any issues with the use of the reservoir for
         clutches. There may be something in the manual transmission manual about that, but since I have an
         automatic I don't have that manual.

         You are correct about not pushing the brake pedal down (especially to the floor) when bleeding the
         system as it can push the master cylinder seals to their limits or rub them up against corrosion. That is
         one of the main potential problems with the old two person approach to brake bleeding, and thus the
         popularity of pressure bleeders. However, even with pressure bleeding you still should do some "pedal
         pushing". In the Volvo shop manual they suggest that after you have connected the pressure bleeder (but
         obviously before you open up any bleed nipples, you should "depress brake pedal a few times to expel
         any air bubbles from the master cylinder. Note: Repeat this step between bleeding each brake caliper".
         At the end of all the brake bleeding, they also suggest checking to see if there is any more air left in the
         system, by "depressing the brake pedal sharply . With the engine off and the brake pedal depressed 3-4
         times, the pedal travel should not exceed 40 mm". In these preceding procedures, since you have the
         bleeders closed when you are pushing the pedal you shouldn't have much travel in brake pedal and thus
         no problems with seal damage.

         Garth

... posted by Ray Niblett  on Wednesday, 7 March 2001, at 8:45 p.m. ...in response to "Re: 850
         brake fluid replacement procedure" posted by Garth Gullekson.
 

         Thanks Garth. I'll be printing out your post and will store it
         with the pressure bleeder.

         --
         Ray Niblett 95 855 GLT / 98 S70 T5M
 

... posted by Vladimir  on Thursday, 8 March 2001, at 4:00 p.m. ...in response to "850 brake
                     fluid replacement procedure" posted by Garth Gullekson.
 

                     Garth Gullekson wrote:

                     > ..... , and then right
                     > front and finally left front. Since I have the UK Haynes manual but
                     > have a left hand drive car, I assume the front sequence should be
                     > inverted for me. .....

                     Garth, as far as reversing the procedure from your UK book on the front wheels. I think the intent of the
                     Haynes manual was to start the bleeding from the longest brake line and finish with the shortest. So,
                     assuming UK cars have the master cylinder in the same location as the rest of the world (left) you should
                     not alter the Haynes procedure to correct for the steering wheel being on the wrong side of the car. It
                     seems that Volvo manual recomends the opposite of the Haynes. You start with the shortest brake line
                     (front left) and finish with the longest (right rear). Hmmm, I hope one of the wise ones on this board will
                     enlighten us about this as I too am waiting for the warmer weather to change my brake fluid with the
                     Power Bleeder.

                     I haven't decided what fluid to use as Volvo recomends DOT4+ and I am not sure this exists except at
                     the Volvo dealership.

                     As far as clutch is concerned, I think it has to bled as well because it shares the fluid with the brake
                     system.
 

                     --
                     Vladimir. 1998 S70. Base, 5-speed manual.

                     hey,
                     If you are just flushing your brake sytem fluid it should not matter which wheel your start from.
                     If you has air in your system- simply start from the wheel farthest from the master cylinder.
                     I used the Motive Products Power Bleeder and it worked very well. FWIW, I started at my right rear
                     and worked each wheel in a counter-clockwise manner.
                     I used almost 2 full quarts of valvoline sythetic dot 4 brake fluid to flush he entire system. Flush until you
                     see clear fluid !
                     Cannot say enough about the Motive Products Power Bleeder - in my opinion, it was a bargain at $44 !

                     Good Luck