1. Home
  2. Volkswagen, everything else
  3. A2 Brake system flush, how to?

A2 Brake system flush, how to?

Hi... Posting for a friend with a 1991 Jetta TD 310K Kms on it... and what he thinks may be the original brake fluid after doing his rear drums on the weekend. (it's black... and his car doesn't stop all that well - He did the GLI vented disk conversion up front, and with these new rear shoes he can lock the rear up... but he says his old Jetta, a 1990 TD could stop better - and my old 1991 Golf seemed like it could stop on a dime... until brake fade set in at least)

He's done tons of work on various cars (worked in a garage for a while) but he said he never did a full system flush, and doesn't know the procedure... How is this done - vacuum pump? Let the lines drain out?... How do you tackle the fluid in the master cylinder?

We went on to assume that once as fluid is drained you open the bleeder screws and bleed normally... just adding a LOT more fluid then for a normal brake job...

Reply to
Rob Guenther
Loading thread data ...

I think what you do is open the bleeder screws one at a time starting with the one farthest away (right rear), have a helper pump the pedal (it'll want to go to the floor but use short pumps like as in normal braking...don't push the pedal farther than you normally would in normal braking/driving), let the reservoir drain a little bit (but don't let air get in either...don't let the reservoir totally dry out) this first time so you have room to add clean fluid, add more fluid, pump some more, until the fluid coming out is clean. Tighten bleeder screw, repeat for left rear, right front, left front.

Someone jump in if I misstated anything...thanks.

I think the only other word of caution is that the bleeder screws can be frozen on older cars so don't force it. If if feels like you might snap it off you probably will. Get professional help if you feel you might do damage.

Reply to
Matt B.

That's pretty much it. I would use gravity only, no pump. Use a suction bulb or something to get all the old fluid out of the MC. Fill to brim with new fluid, replace cap on both MC and bottle. Open the RR bleeder. Leave it open and let the fluid drip out. When you see the black fluid turn to clear, Close the bleeder. Refill reservoir as needed. Don't forget and let it get too low or you will get air in the lines. Repeat for LR, RF, LF. This takes longer, but one person can do it and it's easier on the system.

Note: Some cars don't gravity bleed as well, probably due to the design of the system. It worked fine on my '87 Jetta.

Reply to
Rex B

Always have fluid in the reservoir... suck out the old stuff first, then fill to near the brim with fresh stuff. Keep topping up.

Using the pedal makes it much quicker; but you need more legs on the job.

If the rear axle has a brake pressure limiting valve and the rear wheels are off the ground, compress the plunger on the valve; else it'll take a very long time to bleed; especially with "gravity" doing the job.

Reply to
Bernd Felsche

I can show you pictures of my Rabbit after the rear brakes locked up. I rolled into a telephone pole. That hurt me and the car.

I just do as Bernard says. Empty the old fluid out and start pump>Hi... Posting for a friend with a 1991 Jetta TD 310K Kms on it... and what

Jim B.

Reply to
jimbehning

Thanks to all that responded, the info has been passed on.

Reply to
Rob Guenther

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.