tires and wheels Brake and clutch bleeding

[bob02]

Hi all,

I've had my 71' on stands for a few weeks, primarily to change the RTAB'S and the oil pump. While i was at it , i decided to change the brake fluid, front pads and flip the clutch slave 180 degrees(5 speed) so the bleed nipple would face toward the ground. (Also, the car has the volvo/320i big brakes up front.)

Now, after bleeding both systems 4 times, the brake pedal still has an unaccepable amount of travel, but is solid when pushed to its' limit. The clutch works fine(ran the car on jackstands), but when in neutral, the rear wheels turn. they can easily be stopped with hand pressure, and i don't think the car would roll if it were on the ground.

I have been using a Motive pressure bleeder each time. One mistake i made was to remove the slave while the system was pressurized, overextending the slave shaft. Other than the wheels rolling in neutral, the car shifts fine.

i'm about ready to get medieval on this bastard. Any insight as to what i'm doing wrong? Thanks in advance!!

bob newman

[BillWilliams]

Will your brakes pump up firm? If so - bleed more, maybe the old fashion pump three times and hold. This has to do a lot with a weak pedal.

If the brakes stay the same after pumping, I would take a whack at tightening up the rear brake shoes. That has a lot to do with a long pedal.

[bob02]

Thanks for the reply, Bill. Yes they do seem to get a bit more firm with some pumping.

Things i left out in the original post were:

rear drums were adjusted

Tii master cylinder 8k mi. ago

Drums within spec

Pressure bleeder filled with .5 liters each time

RR,LR,RF,LF,Clutch was the bleed sequence

I drove in my yard this morning and it does indeed stop, and does not move on its own while running in neutral. Shifts fine also. I'm guessing there's still a little air in the system? I'm hesitant only because i don't want to waste more Super Blue if i'm missing something bigger.

One other thing, is it bad practice to pump the brake pedal while the system is pressurized? While each nipple was open, i stepped on the pedal a couple of times thinking that may help release any trapped air.

bob

[BillWilliams]

One other thing, is it bad practice to pump the brake pedal while the system is pressurized? While each nipple was open, i stepped on the pedal a couple of times thinking that may help release any trapped air.

Not quite sure what you mean in the first phrase. But on the second point, if you have bleeder open and press on the brake pedal, it will draw in air as the pedal is released.

If you want to pedal bleed, you need a container with a tube on it, the end of the tube needs to be in some old fluid in the bottom. Put a wrench on the bleeder screw, put the other end of the tube on the bleeder screw, Have an assistant pump the brakes three to five times. Then have the assistant hold the pedal down. Release the bleeder screw for a second or two tighten the bleeder screw and THEN the assistant can release the pedal. I have seen seasoned vets not use the tube and bottle thing with success.

[TobyB]

they can easily be stopped with hand pressure

When in neutral, that's totally normal- the drag from the trans fluid

carries some of the rotation through the trans.

It often doesn't do it hot.

t

[bob02]

Hi Bill,

What i meant was having the motive attached and pressurized, opening a bleed nipple, then steeping on the pedal. At the end of the nipple i have a device attached that is very similar to your gatorade jug setup. I tried it and didn't feel a difference in the end.

Just drove it for a bit and it stops fine, it's just that the pedal does not have the same feel and travels a bit more than in the past.One big plus is the change from cheapie semi metallic pads to Volvo OE pads- initial cold bite is much nicer!

thanks again guys,

bob

[c.d.iesel]

.....and I hope you have "NEW" - full thickness front rotors also ??

thin cut rotors will contribute to longer pedal

do not treat lightly the correct rear drum adjustment - THAT also is the leading cause for long pedal travel

and of course any changes you made in installing the master cylinder and any 'adjustment' changed at the master pedal linkage

always rebleed the entire system after driving for a period as

trapped air has a way of working it's way around in traped

sections of the system.

stay with the pressure bleeder method - but you must see a

very strong flow of fluid whenever you crack open a bleeder

(including the clutch slave) if you see just a weak trickle -

you have either blocked bleeder nipple, junk in the caliper, poor hoses...

and forget the cost of wasting BLUE fluid - it requires as much as it takes to flush out the old fluid, and tiny bubbles.

My opinion is to not use BLUE fluid - for many reasons......

CLEAR/YELLOW DOT 4 stuff is excellent, and 'readable'.

[bob02]

Thanks C.D.!

The rotors are within spec(<4k mi.) and while there's only 25 miles on it since, I think the new pads are mating with the rotors well.

Even though i adjusted the rears, i think i will try once again. It seems like those adjusting bolts have either an 'on or off' position-very sensitive!

Also, thanks for the great lubrication diagrams!

As for the super blue, it's what i had in the garage. I use either that, or the type 200. Rm european has ATE for 11.95 w/ free shipping and no tax outside of CO. Local retailers want >20.00 for the stuff. Rediculous,imho.

The plan is to bleed them once again, after a few more miles, hoping any air left in the system will be dislodged.

bob

[BillWilliams]

Uncle CD - Merry Christmas first of all.

Secondly, you mentioned a certain length of the brake rod that goes from the pedal to the booster. Do you know what that length is?

Thanks!

[allbim]

Are there shims between the caliper pistons and the pads?

If so, make sure these are not bent or warped.

If they are, the pistons (and pedal) have to travel farther before significant force is applied to the pads.

Keep us posted.

[bob02]

The Volvo pads come with shims and i used them. Nice and straight when installed. I'm hoping that now after a couple of drives, the next bleed session will give me the pedal i'm looking for. The good news is that it the resivoir level has not changed, so i'm guessing i didn't damage the slave or the m.c. I'll post the results when completed.

Off topic; the new poly RTAB'S are nice and the new oil pump has restored the pressure. Maybe now i;ll finally install the single sidedraft that has been sitting and staring at the car. We'll see, as it took me 5 years to install the oil pump!!

thaks to all who replied!

bob newman

[c.d.iesel]

Bill - I'm still looking for that rod length?..................

[BillWilliams]

Thanks CD. When I took mine apart I failed to index it and have not been able to find the spec. Some of the smart guys here say the adjustment is only to make the pedals equal height and do not affect pedal feel.

But if you find a length, please post it up (with a photo/picture)