bad brake fluid leak
- Mitch Covington
- 356 Fan
- Posts: 200
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- Location: Asheville, NC
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bad brake fluid leak
I have a really bad brake fluid leak, car undriveable, big puddle under this access panel under the center of the car floor pan. What's the likely leak source? This boomerang-shaped access panel looks like it'll be hard to remove. Is this area accessible from within the car? There is no sign of fluid anywhere around the master cylinder that I can see/feel from accessing the reservoir/Master cylinder from inside the frunk access panel. TIA.
Mitch Covington
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
- Ken Tuvman
- 356 Fan
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- Location: Lake Minnetonka MN
Re: bad brake fluid leak
The boomerang shaped piece is what secures your brake / clutch pedal assembly to floor. Based on picture, it looks to me that leak is coming from brake master cylinder - possibly the metal tubing that feeds fluid to the brake calipers or slave cylinders (depending on drum or disc brakes). But you're saying no sign of fluid - you'll have to trace the brake line fittings to figure out where you're losing fluid. Maybe left front wheel brake hose? Seems closest to where leak is . . .
Interested to hear what others have to say . . .
Interested to hear what others have to say . . .
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- Martin Benade
- 356 Fan
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- Location: Cleveland, Ohio
Re: bad brake fluid leak
It’s most likely that the piston seal is letting brake fluid leak onto the floor, and spreading from there. I had this happen a couple of years ago, it went undetected long enough to wick pretty far in the fairly young carpet too.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna
- Doug McDonnell
- 356 Fan
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- Location: Augusta,Michigan
Re: bad brake fluid leak
Remove your driver's side floorboard to access the most likely source mentioned by Martin. If confirmed you will need to remove your brake master cylinder which is done from under the car.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.
- John Brooks
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Re: bad brake fluid leak
Mitch
That’s typical of a master cylinder leak. Be sure to clean the lines and fittings with a small wire brush. Then a couple drops of penetrating oil on the lines and threads. The brake line tubing tend to rust inside the fittings, and fuse them. Then a use a flare nut wrench on the lines. Be careful the tubing does not twist with the nut when removing the nuts from the master cylinder. If it does, re brush the lines and re oil. It’s an east fix to rebuild the cylinder or replace it with a new one. Be sure the push rod has the 1mm clearance free space space after reinstalling the master cylinder. Not all that complicated just a pain to get to, and NOT twist the tubing when taking it apart.
That’s typical of a master cylinder leak. Be sure to clean the lines and fittings with a small wire brush. Then a couple drops of penetrating oil on the lines and threads. The brake line tubing tend to rust inside the fittings, and fuse them. Then a use a flare nut wrench on the lines. Be careful the tubing does not twist with the nut when removing the nuts from the master cylinder. If it does, re brush the lines and re oil. It’s an east fix to rebuild the cylinder or replace it with a new one. Be sure the push rod has the 1mm clearance free space space after reinstalling the master cylinder. Not all that complicated just a pain to get to, and NOT twist the tubing when taking it apart.
John Brooks
62 Roadster
66 912
84 Cab
getting pushed around in porsches since 1965
62 Roadster
66 912
84 Cab
getting pushed around in porsches since 1965
- Mitch Covington
- 356 Fan
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Re: bad brake fluid leak
Yep, it's a mess inside the cab... what's the best cleaning detergent for brake fluid? It's all down the tunnel too, will be a tedious chore to clean that out from under the cables.
Mitch Covington
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
- Martin Benade
- 356 Fan
- Posts: 12353
- Joined: Wed Nov 23, 2011 10:52 am
- Location: Cleveland, Ohio
Re: bad brake fluid leak
Jack up the rear so it runs forward. I’d soak up most of it with paper towels. Then most any solvent will work such as paint thinner or lacquer thinner.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna
- Mitch Covington
- 356 Fan
- Posts: 200
- Joined: Mon May 05, 2008 4:02 am
- Location: Asheville, NC
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Re: bad brake fluid leak
This pile of insulation was in the tunnel... rat nest, or is there a reason to have insulation in there? I suspect a nest, as there were a couple of feathers in there too...
Mitch Covington
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
- Mitch Covington
- 356 Fan
- Posts: 200
- Joined: Mon May 05, 2008 4:02 am
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Re: bad brake fluid leak
The previous owner retrofitted disk brakes on the front, so I suspect that this is not the original master cylinder? This is a '59 Cabriolet.
Mitch Covington
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
- Doug McDonnell
- 356 Fan
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- Joined: Sat Apr 05, 2008 8:21 am
- Location: Augusta,Michigan
Re: bad brake fluid leak
Rat/mouse nest for sure. And dual Master Cylinder upgrade which works fine for disc or drum brakes and safety feature not found on a 356 when new.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.
- Martin Benade
- 356 Fan
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- Joined: Wed Nov 23, 2011 10:52 am
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Re: bad brake fluid leak
The replacement will ideally be dual and specifically for disc front drum rear, I think 1968 Karman Ghia is that. This gets the correct type of residual pressure valves. You’ll have to drill out the threaded mounting holes to 8 mm.
What kind of rats have feathers?
What kind of rats have feathers?
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna
- Mitch Covington
- 356 Fan
- Posts: 200
- Joined: Mon May 05, 2008 4:02 am
- Location: Asheville, NC
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Re: bad brake fluid leak
Thanks, didn't realize this was a VW part, but sure enough, this seems to be the exact one here. I'll have to drill out the mounting holes? Darn.
Mitch Covington
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa
- Martin Benade
- 356 Fan
- Posts: 12353
- Joined: Wed Nov 23, 2011 10:52 am
- Location: Cleveland, Ohio
Re: bad brake fluid leak
Yes, just a cleanup to remove the threads. But look a bit further, you’ve found an all drum brake one. The Ghia one looks identical but is set up for front discs. Also if it specifies, 19mm bore is what you want. Bigger will not be better.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna
- Doug McDonnell
- 356 Fan
- Posts: 6081
- Joined: Sat Apr 05, 2008 8:21 am
- Location: Augusta,Michigan
Re: bad brake fluid leak
Try Klasse 356 for a Master cylinder.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.
- Martin Benade
- 356 Fan
- Posts: 12353
- Joined: Wed Nov 23, 2011 10:52 am
- Location: Cleveland, Ohio
Re: bad brake fluid leak
They only offer all disk or all drum. Chances are either would function, but not as correctly as the KG one.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna