Brake bleeding, '64 230sl

[enochbell]

I am having trouble getting the brakes back workin on my '64 230sl.  I just had the two from calipers off (disconnected from the brake lines) and after reassembly I was unsuccesfull bleeding the brakes: pumping/opening bleeder valve/pushing pedal to floor/closing valve/returning pedal/beging downstroke on brake pedal while opening bleeder/closing bleeder at bottom and then repeating ABOUT 50 TIMES! No brake fluid produced through the bleeder.

So what is wrong?  Air in the master?  Tried the same procedure on the master bleeder (I hope there is only one, facing upwards and just under the master cylinder).  Same results, I can push no brake fluid through the bleeder.

Am I doing something really dumb or might I have a bigger issue.  The brakes worked fine before I took the lines apart.

Your assistance would be really appreciated.  Can't go the whole weekend driving with the e-brake :-)

Thanks,
greg

'64 230sl, fully sorted out...ooops, spoke too soon

[hughet]

If your brake hoses are older than 10 years I would recommend that you replace them. When they are old they seem to swell up inside and even stretch a bit when they are under pressure.
I know this because a few years ago I flunked a safety inspection because my rear (drums) were hardly working. It turned out to be the hoses.

[enochbell]

Thanks, Hugh, the brake lines are all "new" (done 5 years ago, with about 7k miles since then).  I think the answer lies elswhere.  BTW, I have checked all of the brake connections and none are leaking (although with the inabiity to bleed these I suspect I have not got enough pressure to really test them properly)

Thanks, still looking...
greg

'64 230sl, fully sorted out...ooops, spoke too soon

[waltklatt]

Greg,
Disconnect the line from the caliper to the master cylinder to see if any fluid is dribbling out.  If nothing, bthen your blockage lies further up the line or the master is out of order.
If you get fluid coming out then the problem is inside the calipers you just rebuilt.  Did your replace all the seals and install them properly and use the correct torque settings to bolt them back both halves together?  When bleeding it's best to have two people-one to pump the brake pedal and the other to open and close the valve.
Just a clarification on the picture as I'm not clear on what you have done to bleed the brakes.  Also it's best to start from the farthest wheel(right rear), then the left rear and then right front then last is the closest to the master cylinder the left front.
Let us know if this works.
Walter
1967 220SL diesel-a first run around the block after 34 years of being immobile.

[George Davis]

Greg,

air in the master is possible.  I'd suggest disconnecting the front brake line at the master cylinder, then bleed it by the pedal down/block hole with finger/pedal up/unblock hole/pedal down/block hole/pedal up procedure.  Once you get good shots of fluid when pushing down the pedal, reconnect the line as quickly as you can and hopefully you can now bleed as normal.

Naturally you must not let any brake fluid get on the paint, or wash it down quickly with water if it does.  Good luck!

George Davis
'69 280 SL Euro manual

[enochbell]

Walter,

Thanks, yes, I used a helper to operate the brake pedal while I opened and closed the bleeder.  I believe I am doing it correctly, I have done it successfully on other cars (but never on ABS units!).  Also, I did not rebuild the calipers, all I did was disconnect them ( at the rigid brake line that snakes behind the kingpin) to do some front end work.  No rebuild, no touch nothing, I swear.  And yes, I started back right,then left, front right, then left, then master.  Got a little squirt from the front right, a tiny amount from the master, but they certainly are not bleeding properly.

Thanks, HELP

'64 230sl, fully sorted out...ooops, spoke too soon

[enochbell]

George, thanks, I bleeding the front line from the master, I will let you know,

THanks,
g

'64 230sl, fully sorted out...ooops, spoke too soon

[waltklatt]

If there is a little squirt from the front line, then it is blocked somewhere along the line.  Open up one of the lines to the master cylinder itself to see if the fluid sprays out there.  If not then take the two 13MM nuts and washers holding the master to the booster and seperate them carefully to see what the back of the master looks like.  Do you have peeling or bubbling paint on the booster under the master?  Then that's a case of a bad master cylinder.  Also if you filled up the master reservior and the fluid level goes down then it's leaking into the booster cavity.
You will need to remove the booster to drain or siphon out the fluid from inside.
Walter

[enochbell]

George, I opened the front line off the master and bled using finger/hole method, that produced good squirts of brake fluid.  I will retry all four corners tomorrow: unfortunately I just lost my "helper" (my teenage daughter was non too thrilled about working in this hot garage anyway).  Thanks, I will let you guys know tomorrow,

Appreciate the help, as always,

greg

'64 230sl, fully sorted out...ooops, spoke too soon

[enochbell]

OK, I'm back with renewed commitment but growing frustration.  I can not bleed these brakes. The brakes were fine before I began work on the front end. Here is what I have done:

1) Removed the front calipers, left the lines open for a few days while car was on jacks and I was doing the front end.
2) Reassembled everything, (the front end is all together and aligned properly, what a difference...driven with the e-brake 1/2 mile to the alignment shop and back).
3) Tried to bleed brakes, using conventional method.  RR, RF, LR, LF.  Produced minimal spits of fluid at each wheel, but not enough to move any significant amount of fluid out of any bleed valve.
4) Tried to bleed master cylinder, at master bleed screw.  Same thing: couple of spits and then nothing.  Opened the front pipe (which I believe feeds the rear brakes) at the master, this produces normal squirts of fluid when pedal is depressed.
5) Went back around all four wheels, same dissapointing results: couple of squirts at first and then nothing.  I tried a minimum of 20 pedal pumps at each wheel.

Before I give this up to my mechanic, is there any other approach I should try?  

Thanks for the advice, I appreciate it as always,

g

'64 230sl, fully sorted out...ooops, spoke too soon

[blairwag]

Greg,

You definitely have the MC fluid resevior full of bake fluid, right?

If so, here are my recommendations:
1) reconned all of the system, and attempt to bleed again. This time, be patient. Perhaps you just have TONS of air in the lines because ALL of the fluid drained out while you have the calipurs off for days.

2) Consider a gravity bleed - removing the MC fluid resevior top, and opening one of the bleeder plugs on a slave. After hours - you should have fluid slowly dripping out of the bleed plug.

3) Have you attempted to bleed the rear lines? You haven't opened these, right?

4) IF these fail, you've got one of 2 problems:

A) blown master cylinder - seals blown, so fluid is pushing passed the plunger, behind the seals.

B) a seriously blocked set of brake lines.

Good luck - let us know how it goes.


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[JimVillers]

Greg .... Make sure that the fluid reservoir is FULL so that it fills both sides of reservoir (back and front).  Remember that you have two brake systems that you are trying to bleed at the same time.  When you get one bleed and firm, the other will not pump and bleed the same or easily.  You just need to work at it and all of the air will eventually come out. Remember, keep the reservoir FULL so that both sides have fluid.  

Now you know why pressure bleeders are so popular.


Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

Watching this thread , I have the same thoughts as Jim..
.. what you want to know is that the rear section of the res will NOT fill up until the front one is completely full.. these early systems have a seperation wall inside the res and the only way the back one fills up is from the overflow of the front one.. which flows over the seperation wall to the back..
The later ones had fluid level sensor/warning lamp , so this did not happen .
Look real good with a strong light and see that both sections are full before attempting to bleed..otherwise you are pumping nothing but air.

[enochbell]

Problem solved, some question remains (in my mind) about cause.  

Thanks for all suggestions, I tried them all to no avail.  Finally took the master cylinder out to check, I could not see anything wrong but took it to my local independent for second opinion.  He diagnosed stuck check valve on first stage (middle valve serving front wheels).  He cleaned it, bench bled the master, and when I reinstalled the master the problem was solved.  All four corners bled as normal, brakes work fine.

Now, I don't pay $'s for my mechanic's work (I trade him business consulting time) so I never worry about his motives, plus he is a decent and fairly knowledgeable guy, though not an expert on W113's.  But might bench bleeding alone have fixed the problem?  Is the check valve a replaceble part?  He said no worries, the problem should not return...

I don't throw golf clubs or wrenches, but this was as close as I have ever come to the latter.

Again, thanks for the advice and suggestions,

g

'64 230sl, fully sorted out...ooops, spoke too soon

[A Dalton]

Dirt in check valves of master can often be a result of using the pedal pumping method of bleeding, which is one of the reasons  that pressure,vac, or gravity techniques are better.
 You just don't want that piston traveling out of it's normal stroke length any more than possible.

[rwmastel]

quote:Originally posted by A Dalton

Dirt in check valves of master can often be a result of using the pedal pumping method of bleeding, ....

For educational purposes, where would this dirt come from?

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[mdsalemi]

quote:Originally posted by rwmastel

For educational purposes, where would this dirt come from?

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

Rodd, being the "proud owner" of over 80 check valves that control the flow of chemicals and water at the car wash--(and incidentally each one needs to be rebuilt annually)--they get dirty from contaminants in the fluid that flows over them.  Seals degrade as well, and over time the dirt collects on the sealing surface of the check valve....when they say change your brake fluid annually, they mean it.  Also, the automatic machines that hook up all 4 calipers and the master and pump a lot of fluid through the system are a good way to clean it all out.  I have not done the old pump and dump method of bleeding since the 1970's--I bite the bullet and take it to a place that has the equipment to do it all automatically.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[graphic66]

http://www.bmw-m.net/TechProc/bleeder.htm  
I made one of these up and brake bleeding is now a one person job and very easy.

[mdsalemi]

quote:Originally posted by graphic66

http://www.bmw-m.net/TechProc/bleeder.htm  
I made one of these up and brake bleeding is now a one person job and very easy.

Fabulous!

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored