71 Super Beetle convertible brake fluid leak

[jorgelu17]

Hi there my Samba peeps. I have a 71 Super Beetle convertible. Just dropped the front end and was excited to start driving it around but low and behold I see some brake fluid leaking from a hole in the front undercarriage. My master cylinder is dry underneath, the brake reservoir lines coming out are dry. I'm stumped as to where the leak is coming from. I press the brake and pump it and hold it down for 5 seconds and it still stiff. It doesn't lose braking power. Please help!!

[ashman40]

[Cusser]

[jorgelu17]

Ashman thank you for that visual and explanation. How difficult is it to change out the MC? I do have some mechanical experience but not much with my bug. Or what is the usual costs to have someone change it out for me?

[jorgelu17]

Hi there Cusser. Thanks so much for the response. This also helps me out quite a bit. I appreciate it! Same questions. is this job hard to do? i do have some mechanical experience but not much on a vw bug. or what is the usual costs to have a mechanic do it for me? Thanks.

[jorgelu17]

Also is the bug drivable? Is it safe to drive as long as I check that the reservoir has brake fluid. It goes down but very slowly. Thanks.

[Cusser]

[ashman40]

Any leak in the brake system is a danger that should be repaired ASAP. There are folks that drive around knowing they need to pump their brakes to get the car to stop reliably, that is just too scary for me.

MC replacement is really not that hard. It only requires a one specialized wrench (flare nut wrench) to loosen the steel brake line flare nuts. You can make do with an open end wrench but run the likelihood of buggering up the flats of the brake flare nuts.
Having a turkey baster is also helpful to drain the brake fluid reservoir before you disconnect anything. This is ti reduce the spillage of brake fluid all over the place.
You will need to bleed the brakes when done so will also need a 7mm(?) box-end wrench to bleed each WC. Having some system to speed up brake bleeding like a brake vacuum or pressure system is helpful to speed things up, but you can make do with some fish tank air hose a glass container and a buddy to pump the brake pedal.

You will want to remove the gas tank and the left front wheel to gain access to the MC.

You need to be careful when removing the two bolts that hold the MC in the bulkhead. There are sleeves inside the bulkhead that will fall down into the gap if you don't take steps to collect them before they fall. When you loosen the two bolts holding the MC in place do not remove the bolts completely or the sleeves will fall down into the gap and you will struggle to fish them out. Note in the pic below the loosened bolt (right) has not been removed.

I wouldn't even pull the bolt out that far. You only need to pull it out far enough that it is no longer engaged with the MC flange.

While you are replacing the MC you should consider replacing the two brake fluid specific "blue" hoses that run from the brake fluid reservoir to the MC.

When working with brakes you want to be meticulously clean. Any dirt/oil in the brake fluid will compromise the system.

Buy the large size DOT-3 brake fluid bottle as you will want to flush the brake fluid out of the entire system when done replacing the MC. Brake fluid WILL eat paint. If you spill any be sure to quickly clean it up with paper towels and brake cleaner to flush it off the painted surface. So if working on a garage with a treated/coated surface you may want to lay down a plastic sheet. A couple cans of spray brake cleaner will also be needed.

These are not the only steps for replacing the MC. Find a YouTube tutorial or better yet find the brake section in the Bentley manual.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[polypetalous]

Just re-did the brakes on my '74 super...
Not sure if '71 is different, but pulling the gas tank DID NOT allow me any better access to the Master Cylinder or anything... perhaps slightly easier to change the hoses from the reservoir to the master cylinder.

Ultimately I needed to pull the gas tank anyways, but really didn't "help" with my brake job.

Also, I was super nervous about losing the spacers that the master cylinder mounts with, only to find that mine were missing.
I made up some new spacers, and then proceeded to drop them a couple of times while cutting/fitting... it wasn't impossible to fish them back out.
Though of note, I also did NOT find the original spacers while digging around, bummer.

Honestly the brakes on these cars are pretty easy to do, lines and all...
I DID NOT bench bleed the master cylinder though, we will see if that haunts me.

Ben

[Cusser]

I've owned my 1971 Super since 1976, so have changed out the brake master cylinder about 5 times (guessing, because I don't want to look it up); before the Dec-2020 replacement, the previous one had lasted over 20 years. And I NEVER removed the gas tank for such job, and have never ever removed its tank at all.

Good time to replace the special feed-line brake hoses too, special rubber formulation.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[jorgelu17]

Thank you all for the good information. I will tackle this job this coming weekend! I will be buying a German made MC from JBugs for $105.00. With the info you guys have given me I am positive I can do it myself. Thanks once again my Samba peeps!

[ashman40]