What's wrong with my brakes?

[ZeroAxe]

The Stock MC of Beetles keeps some pressure in the system so that the brake shoes just slightly drags on the inside of the drum. This eliminates you having to push hard on the pedal to make contact between the shoes and drum. That is why it is so important to adjust the shoes/brakes regularly. As you should know, the drum brakes are not self adjusting. So there have been very few SUCCESSFUL conversions with disc brakes and stock MCs. At some point, you will have problems.

I would say another thing is the free-play in the MC's rod(actuator). This will amplify the pressure build-up problems if it cant retract far enough. So get the checked out SOON.

[Merlin]

We (family) have discussed it before, and quite frankly one of the following is likely to happen here now...

1. Fix the damned brakes and sell the car.

2. I pay to sort out the brakes with a different m/c, etc.

3. We fit '66 drums back on it - I am SO tempted... - solves clearance/adapter issues, brake issues, etc.

I'll have a chat with those concerned and we'll see what happens.

Thanks, N.

[ZeroAxe]

Seriously, if you plan on selling the car anytime soon, why NOT change back to drums?

[Merlin]

Seriously, if you plan on selling the car anytime soon, why NOT change back to drums?

We don't *want* to sell the car - therein lies the problem.

The PO of this car for lack of a better description, #$%^ed it up. S/He "hotrodded" it period-style and none of the mods are correct by today's standards, so since day 1 I've been slowly correcting it.

We've redone the engine, and the linkage, and shortly, the carbs.

The front suspension had leaves pulled - I have a repair donor for this.

The brakes...

...and a whole host of small issues which I've corrected.

The car was bought with the assumption that we could drive it from day 1 as a reliable daily - it's been a rollercoaster though.

It's getting there now but my father didn't buy it as a resto project so he's not keen to spend on it - which is why I'm doing it. It's now my mother's bug, and she loves it, but we all wish it would just run sweetly for once and for all.

I haven't decided what to with the brakes yet, and we haven't decided on it's Fate as yet either...

[hitlers revenge]

When I did my front disc brake conversion, thats all I did. I didnt touch anything else which is all stock standard. I had no problems in all the time the discs were on the car. I would say that your problem lies in the rubber brake hoses which I suggest are blocked.

[Merlin]

When I did my front disc brake conversion, thats all I did. I didnt touch anything else which is all stock standard. I had no problems in all the time the discs were on the car. I would say that your problem lies in the rubber brake hoses which I suggest are blocked.

Brake shop reports that the bug's brake system bleeds easily, with no blockages.

[SUZIE]

Merlin , nic it could also be just a litte bit of dirt in the breakfluid that couse this problem, let them flush bleed the brakes and test it and see what happens

[Merlin]

Merlin , nic it could also be just a litte bit of dirt in the breakfluid that couse this problem, let them flush bleed the brakes and test it and see what happens

Been done and the owner is driving the bug to see if the problem reoccurs.

Thanks, N.

[forcecooled]

Fffffffffffaaaaaaaaaak , Nick.
How much more Kuk is that bug going to give you.?
The brake problem that you are having is probably due to the PO leaving the original MasterCylinder, or replacing it with a new standard one.

Disc brakes rely on a thing called "rubber roll back" of the rubber seals to lift the caliper piston minutely off the pad , this allowing the wheel to turn relatively freely when you lift off the pedal. (you will always have the pad touching the disc to a slight degree, mainly resulting a slight scraping noise)
To employ the roll back feature to its full extent, the system has to have a MC that allows fluid pressure to bleed EASILY back to the brake fluid bottle.
If this does not happen, and especially when you have dirty fluid, rust and a little bit of air in the system,things expand and drillings can block up, and you can have the lock-up on the wheels with disks like you had.
To put it very plainly, the MC for a disk system has one more drilling in it than an MC designed for a drum and shoe system, or was designed specifically for a disc system..
Many people run the local tang en draad disc brake conversions for years with a standard MC without problems untill all the factors that require that extra drilling come into play---- and they have a lock-up.
If the hoses were causing the problem, its unlikely that you would have both front and both back sets fail at once. And , if one hose created its own non-return valve, you would have the offending caliper / hose / wheel locking up, and the car would want to pull to one side.
The issue of incorrectly adjusted pedal / MC push rods is also a very valid one.
Its normally a bunch of problems (like seized "on"rear wheel cylinders or faulty handbrake linkages) that manifest themselves at the same period of time and cause these problems. Be carefull of fitting dual circuit golf type master cyls untill you have checked out the specs and bore sizes. remember most of these systems were designed to operate in conjunction with a booster. Try stomping on a golf pedal when it is free wheeling downhill at a fair lick with the engine off and the booster void of vacumn, and see how pisspoor the brakes really are in that state.
Start asking your brake specialist some pertinent questions!
Cheers
Bill

[hitlers revenge]

Merlin you say the owner is gonna tst drive it. Make sure they carry a spanner(no.7??) with them. If the whells do lock up, then they can openand close the bleeder screw very quickly to relief the pressure and then carry on driving instead of getting another tow truck. Cause they are bloody expensive.

By the way, I have expierienced this happening to me on the busy N1.

[Merlin]

Fffffffffffaaaaaaaaaak , Nick.
How much more Kuk is that bug going to give you.?
The brake problem that you are having is probably due to the PO leaving the original MasterCylinder, or replacing it with a new standard one.

Disc brakes rely on a thing called "rubber roll back" of the rubber seals to lift the caliper piston minutely off the pad , this allowing the wheel to turn relatively freely when you lift off the pedal. (you will always have the pad touching the disc to a slight degree, mainly resulting a slight scraping noise)
To employ the roll back feature to its full extent, the system has to have a MC that allows fluid pressure to bleed EASILY back to the brake fluid bottle.
If this does not happen, and especially when you have dirty fluid, rust and a little bit of air in the system,things expand and drillings can block up, and you can have the lock-up on the wheels with disks like you had.
To put it very plainly, the MC for a disk system has one more drilling in it than an MC designed for a drum and shoe system, or was designed specifically for a disc system..
Many people run the local tang en draad disc brake conversions for years with a standard MC without problems untill all the factors that require that extra drilling come into play---- and they have a lock-up.
If the hoses were causing the problem, its unlikely that you would have both front and both back sets fail at once. And , if one hose created its own non-return valve, you would have the offending caliper / hose / wheel locking up, and the car would want to pull to one side.
The issue of incorrectly adjusted pedal / MC push rods is also a very valid one.
Its normally a bunch of problems (like seized "on"rear wheel cylinders or faulty handbrake linkages) that manifest themselves at the same period of time and cause these problems. Be carefull of fitting dual circuit golf type master cyls untill you have checked out the specs and bore sizes. remember most of these systems were designed to operate in conjunction with a booster. Try stomping on a golf pedal when it is free wheeling downhill at a fair lick with the engine off and the booster void of vacumn, and see how pisspoor the brakes really are in that state.
Start asking your brake specialist some pertinent questions!
Cheers
Bill

Hey Bill,

Thanks for the heads-up.

I haven't personally checked the m/c on that car and thus won't 100% say for sure that it's stock - or not.

If I understand you correctly, then new fluid, replacing damaged hoses/pipes, etc. *should* sort out the problem for now - if this is the case?

As stated, I was unable to determine which wheels had locked up at the time, but there was certainly no pulling. The brakes were on, hard, and the car slowed uniformly.

I'll give the brake shop a call tomorrow and have a chat about these posts with them.

I don't really have the skills to do the work myself unfortunately (- yet), and my father's seriously pressed for free time as it is, so in times of an emergency...

I know we've tried atleast 3 different m/cs on MY bug (4x discs), and we're currently sitting with a dual-circuit European m/c from WW. I hope we're sorted with that car...

HR: That's why it's at a brake shop - they can sort it out.

Cheers, Nic

[vader]

Photo0901.jpg

This is the Tonii MC that I got for R135... Just buy one and put an end to your problems..

Is your life worth more or less than R135? Just put it in MTM (Merlin The Miser) and drive in safety.... If you gonna sell the car PUT IT IN ABD SELL IT WITH A CLEAR CONSCIENCE!!!! You dont wanna lie at night worrying if the new owner is safe or not....

[Merlin]

I actually either have - or had - one of those, from Mr. Rowley, but that's another story for another time.

It was destined for MY bug, but was one of the options that did not work out.

Problem is, I'm not sure wtF it is.

I sold a fellow forum member a new Golf one I bought too.

I don't sell unsafe cars - nor do I drive them in unsafe conditions (hence the work and this thread) and Vader, mate, a Miser I ain't - you'd choke on your lightsaber if you glanced over some of the bills for my cars.

N.

[vader]

There are just so many words you can use with MTM..... hehehe

[forcecooled]

Vader, ( have to call u this as i dont know your earthly name)

Are the mounting holes at 90 Deg to the inlets ? It is not clear in the photo's.

If they arent,, and you end up mounting the cylinder cocked at 45 degrees, you may have problems in evacuating all the air from the top of the cylinder bore, and have an eternally squishy pedal, unless of course you devise a methofd of pre-bleeding the system before you actually bolt the MC in place.