Hey
In the quest to fix my soft brake pedal, in the last 2 weeks i've put in a new (i'm guessing NOS) master cylinder (good german one) and 2 new rear wheel cylinders.
Bled the brakes multiple times during the process.. adjusted up the rear brakes.. and still have a soft pedal!

This is really driving me up the wall so any help would be greatly appreciated!! :jesus

[ Edited on 21-5-2007 by jo_tas ]

**UPDATE**
Pedal was good and solid for about 2 weeks, then over a couple of days went as soft as it used to be!
We clamped off each line seperatly, and found that when the right rear line was clamped it made a huge difference.
So we bled that line again, as well as all the others. A small amount of air came out but not much.
Adjusted brakes up, but my pedal is STILL soft! ARRGH!!
We mesured the brake drum and it is getting close to maximum size, however how could this cause it to go soft over just a couple of days?
Please help.. this is really starting to annoy the heck out of me!

[ Edited on 19-6-2007 by jo_tas ]

Oh.. sorry for those that don't know this is in a late model type 3..

you may have break lines to the wheels that are swelling under pressure get a mate to push on the pedal while you feel the lines the rubber ones this is not an uncommon thing in an older car

Thanks for the suggestions..
No brake booster fitted..
Will check the brake lines next..

I'm doing this work at TAFE in my automotive course.. with teachers helping me.. and they're running out of ideas so i thought it might be some silly VW thing..

if its got the tafe teachers stumped your in strife!!
make sure there are no obvious leaks. make sure the bleed screw are tight, and the lines on the new master cyl and wheel cyls.
and as greedy said check the brake lines, as these will cause trouble with some age about them. they are only about $25ea to replace.
sounds like there is still air in the system, bleed the longest line 1st, drivers side rear and start again.
i have had trouble with mine before, used heaps of brake fluid before i got all the air out

Is it a soft pedal or just excessive travel and has to be pumped a couple of times in quick succession to get a near full pedal? If so, have you backed the hand brake cables right off before you do any primary adjustments. Maybe the rear shoes aren't sitting on the pistons. Just a thought as this can fool you into thinking you have air in the system.

DH

Check the adjusters where th shoes sit some times people put them in wrong as they are not just like a normal car they have a slight angle on the .
How bout trying some hose clamping pilers,get somebody in the car and clamp all the hoses one at a time starting at the back each time you clamp a line get the helper in the car to try the brakes this will tell you if you have a problem i one wheel or the back or the front and if the pedal stays the same after all the lines have clamps on them ther may be a problem in the master cylinder

Replace the rubber flexiable hose all of them from memory theres 5 on a late type 3

adjust the rear brakes with hand brake loose

then adjust the hand brake

check and adjust the freeplay in the brake pedal in the order above

check the fluid entry line to the master cylinder to see if there fitted correctly and not leaking or sucking air

Thanks guys.. gives me some more to go on next time i can get the car into tafe..

One thing the teacher warned me about is aftermarket wheel cylinders sometimes having different internal capacities to the originals.. ie larger so it takes more fluid (pedal) to fill the cylinder.. I'm hoping this isn't the case as i bought them from a good VW mechanic/parts supplier..

there marked ofn the outside and should be 19mm from memory do u still have the old ones

is the floorpan flexing where the pedal assembly bolts down onto it? that's what mine turned out to be.

Spot on.

The calipers at the front would benefit from new seals too and it is an easy job, good to do @ TAFE too. This and the hoses means a reconditioned fluid system.

The rubber hoses degrade from the inside out. They stop the fluid flowing easily. They can be a bugger to crack from the steel lines sometimes, good to have help if you have not done it before.

The clamp the lines trick as listed in a prev post can help pick out the ones that are most stuffed if you want to do them in two goes (front and rear).

The handbrake right off is important, also check the cables are not siezed in the housings. Did you clean and lube the adjusters?

Go girl and keep those nails dirty!

>One thing the teacher warned me about is aftermarket wheel cylinders sometimes having different internal capacities to the originals.. ie larger so it takes more fluid (pedal) to fill the cylinder.. I'm hoping this isn't the case as i bought them from a good VW mechanic/parts supplier.. <

>they're marked on the outside and should be 19mm from memory do u still have the old ones <

Are you talking about the master cylinder or wheel cylinders (rear) Dave? The rear wheel cylinder on 63-70s is 22mm diameter.

I recall that the early Type 3 squares had a different size master cylinder to the Notch but have loaned my book so can't check that stuff.

DH

PS. Never trust a TAFE Teacher!!




[ Edited on 25/5/2007 by 1500S ]

The Master should be 19mm and the rears should be 22mm I think Wagons had 23mm as well

Well it took the storeman (young guy) to sort it out.
Somehow there was still some air in there.. and the adjustment somehow wasn't right... i don't know how or why but they're working well now so i don't care!!

Thanks all for your help and suggestions.. no doubt this topic with all its great info will help other people!

I've had problems where the brakes wouldn't bleed up before.

I tried and tried one day and just couldn't get the air out, so figured it was trapped somewhere (this was after rebuilding the rear calipers).

So I drove it for a few weeks (leaving bigger braking distances than normal) and then bled them again. I didn't see the air go out in bubbles, but it went out. Suddenly they were perfect again.

So sometimes driving seems to help move the air to somewhere that it can be bled. I think this is a particular problem when you use ford rear calipers like I have, as the caliper is full of all sorts of ratchets and crap for the handbrake, which make trapping air inside the caliper piston quite easy.

Update.. see first post... stupid car!

do type 3`s have the same rubber bung on the top of the master cylinder as a beetle, i had similar in my beetle so changed the whole master cylinder, when i took it out the rubber bung on the inlet hose was cactus, so in hindsight i could`ve just changed that part, but my brakes are fine now with the new master cylinder

Umm i don't remember seeing one there.
I know that type 3 master cylinders are different, as they are dual circuit

Do the brake line clamp test again.

I bet there is some mushy hoses.

We tried that.. clamping the right rear line made a huge difference, the others not so much.
So we tested that line by clamping one end then testing, then clamping the other end. No matter which end of the line we clamped (line included or not) the pedal still comes solid, so it can't be the brake line