Still have front brake issues!

Back in December I had opened a dialogue about some rather strange brake issues I was having, and yesterday I did a bit more work which didn't really seem to help.

Before I did anything, I replaced the stop plate behind the pedals because I could see the brake pedal was coming back way too far (and was probably injecting air!). So with that fixed and adjusted properly ... I moved ahead.

Jim had suggested that I do a "drip test" on the MC. So I unscrewed the hex-switch for the front brakes and let it bleed. Nothing rushed out like I expected. I was supposed to hopefully see some bubbles escaping. I didn't. :-( I did get a solid stream, but it was a small trickle. Then I went back and bled each tire multiple times. But I still have to go all the way to the floor to get any pressure. When bleeding, I didn't see a single solitary bubble escaping. It seems to be all fluid and no air.

Then I pulled off the front tires, and pulled off the hubs to inspect the parts. It looks like the wheel cylinders are working just fine. I also removed the adjusting stars and greased them up, and then reinstalled everything. Then - adjusted each star on each tire until it was just starting to drag on the tire. And then of course, rebled each tire multiple times.

But ... I still have the same problem.

I know I should be adjusted and bleeding the back brakes as well - but that is going to mean replacing the wheel cylinders, which would lead to new lines, which might also mean a new MC. I can't do that right now, so I am avoiding the rear brakes! But that system has never been opened. It's only ever been the front brakes that I have been playing with.

Anyone have any ideas for me? :-)

Thanks,

-Steve Ballantyne

68' Bug
Reply to
steve.ballantyne
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Are you adjusting the back brakes ??? You need to do all four wheels to get a good pedel.

Jerry

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Reply to
Jerry - OHIO

Agreeing with Jerry.

Low pedal is caused by excessive drum-to-shoe clearance (assuming no air or other failure modes).

To test if this is the cause adjust all 4 wheels so tight that they won't spin at all. If you have high, solid pedal then that was it. (loosen them before driving...)

Jim

Reply to
Speedy Jim

" snipped-for-privacy@gmail.com" wrote in message news: snipped-for-privacy@j8g2000yql.googlegroups.com...

you need to adjust all four wheels... when you adjust them till they lightly drag, as you did, get in and push the brake pedal to re-center the shoes and do it again.... if your parking brake handle comes up pretty far, that is a clear indicator(usually) that the rear shoes are too loose...

check the pedal freeplay... you didn't say if you reset the freeplay properly after putting in the pedal stop. the pedal coming too far back will not introduce air into the master cylinder because the rod pushes on a piston and is not part of the internal workings of the master cylinder...

Reply to
Joey Tribiani

Impossible. The master cylinder piston travels all the way to the rear of the cylinder when the pedal is released. Pulling the pedal even further away from the master will do nothing, it is not connected to the master cylinder piston. It only has a push rod, actuating the piston. It cannot pull the piston back. The internal springs inside the master will take care of pushing the pistons back.

That said, the pedal pushrod has to be adjusted so that it FULLY disengages from the master cylinder when the pedal is released. There needs to be about 1mm of free play. It's damn near impossible to measure, but as long as you have some noticeable free play, you are ok. If there's no free play, it means the pedal (push rod) is preventing the master piston(s) from moving back to their resting position. That is BAD. The piston need free, unobstructed travel to it's fully extended position, in order to open a passage for pressure release/new fluid to go in from the reservoir. If it can't move all the way back, teh brakes will act weird, and probably drag, even lock up when you least want them to.

I see one flaw in your procedure above: You need to adjust all brakes from the stars so the drums no longer turn AT ALL. Before doing the same in the rear, you need to disconnect the handbrake cables from the lever end, making sure the levers at the drums are fully relaxed. Then adjust rear shoes so tight you can't turn the drum at all.

Now bleed.

Then adjust shoes again, so that you hear them scrape maybe 1/2 turn of the drum. Test drive, apply brakes going forward and in reverse, then adjust again in the same way.

If you are happy with the foot brakes, then re-attach the handbrake cables. Adjust handbrake lever so the brakes are fully engaged at 5 (five) clicks.

Do the rears. You should start with the wheel furthest from the master cylinder (right rear) and work your way closer.

You MAY be able to bleed the rears through the brake line fitting if the bleeders are broken or stuck. You'll need two people. Only crack the bleeders or line fittings open when someone is applying pressure to the lines. Open them while there's pressure, and close them quick while there's still pressure left (pedal is still on it's way down).

if you like getting messy, I have had good results with 2 people like this: one pumps the pedal, while the other cracks a bleeder open and covers the tip with his finger. Finger is acting as a valve, allowing high pressure fluid to squirt out (everywhere, uncontrollably), but won't allow air in. All you need to do is keep your finger pressed hard against the bleeder. When done, tighten the bleeder down and remove finger.

Sometimes you can chase small bubbles further down the line by rapidly tapping on the brake pedal several times. Not depressing the pedal much at all, just surface tapping as quick as you can. Then one big pump, open bleeder while pressure is up, and close before the pedal hits floor.

On old, used masters, never let the pedal go all the way to the floor. It may get the master cylinder piston(s) get stuck at the end of their travel, dud to rust inside the cylinder.

Jan

Reply to
Jan Andersson

snip

YOU HAVE TO CHECK THE REAR SYSTEM!!!! If your system has never been opened/touched..........how do you know if it is working properly?

Brakes are not something you want to take a chance with. You might hurt your car, yourself or worse someone else like me. Find and repair all problems with your brakes. Rust Penetrant is good to start applying to the brake lines along with slightly tapping on the fittings. You can sometimes slightly loosen the brake line from the wheel cylinder without twisting it off then pull the cylinder off of the backing plate and spin the wheel cylinder off of the brake line while holding the fitting. The brake line fitting may free up when the cylinder is off of it. ;-)

I hesitate to mention heating up the fitting while still attached to the cylinder since you might not have a torch and brake fluid, and that penetrant, is flammible. whoosh. 8^o

All new hydraulic cylinders, hoses, and lines are a good thing if you plan on keeping your Bug. ;-)

JMHO

Reply to
dave AKA vwdoc1

No! :-( But I know what the next step is now! :-)

Actually, I have a *low* squishy pedal at the moment, even with the front stars adjusted to the dragging point (but not the lock up point).

Okay ... this all makes sense. My parking brakes does come up pretty darned high. So high that I have wondered if I should be replacing the cables! I think I need to go to the back of the car and give the rear wheels a full inspection.

Aha! I have *not* been bleeding my brakes this way. For that matter as I previously stated, I have not bled the rear brakes at all.

I joked to my wife the other night that I am never getting rid of my bug, and I plan on being burried in it. Which would be convenient if my brakes should fail and I end up running into a pole. They could just throw the whole twisted mess into the ground and my soul would be forever grateful. And the last thing that would go through my head ... would probably be the steering wheel. Ha!

Jokes aside: I am not driving the Bug at the moment due to the questionable brakes!!

I know what I really need to do is a complete overhaul, but it's just not in the budget. Perhaps I could get new wheel cylinders for the rear wheels, and a couple of new lines for the time being. That would allow me to get my daily driver back on the road with good brakes, and would leave off the rest of the parts I need until the summer.

The most expensive elements seem to be the rubber coming down from the resorvoir to the MC, and those flex-lines on the front wheels (one of which I have replaced). If anyone can suggest cheaper sources or cheaper alternatives for these parts I would appreciate it.

Thank you all for the support!

I'm hoping to get a couple more hours in on this job over the weekend. It's warm today in Ohio, but terribly wet. And being Ohio it will probably be snowing by Saturday!!

Thanks again,

-Steve Ballantyne

68' Bug
Reply to
steve.ballantyne

Its a good thing to inspect your whole sysyem and replace all that in questionable . Is there an issue about your rear wheel cylinders, I PB blast and tap on the beeders before loosening so they don't break.

Also the E-brake cables are adjustable at the base of the handle, also worn shoes and drums can make the cable feel loose.

related thing to think about at this time , if you remove the front drums to replace shoes, you can repack the bearings grease.

I just did the system on my 58 beetle which included all but the steal lines and drums and felt doing the wheel berings would be a good thing knowing this bug has not been on the road in 27+yrs

Reply to
Kafertoys

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