I am experiencing a brake fluid leak behind the firewall so I am planning on either rebuilding or replacing my single tank master cylinder. I've never rebuilt the cylinder so I was wondering 1) is it better to rebuild or replace? and 2) if rebuild, what are the challenges I can expect?
Thanks
Brake Fluid Leak
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Andy_In_SD
- Posts: 64
- Joined: Sun May 31, 2015 7:21 pm
- Car: 1970 - 2000 5spd Roadster, 1966 SPL311-1600 Roadster
Re: Brake Fluid Leak
Rebuild is super easy.
Do the following:
1) Check the cylinder
Remove cap, pump brake watch for back flow (gurgling up, bubbles etc).
If you see no crap bubbling back up and now black crap on the bottom you may only need to bleed the brake system.
If you see back flow, bubbles or sludhe on the bottom, goto step 2.
2) Lets see if it's fragged or rebuild will work.
Get under the dash and disconnect the brake pedal from the master cylinder.
Unbolt the brake like so you can remove the master cylinder.
Now undo the 2 nuts holding the master cylinder on the firewall.
You can lift / remove the master cylinder.
Remove the dust cap (rubber part the brak pedal attaches to.
Using ring pliers or needle nose pliers or even a screw driver, remove the ring under the dust cap inside the cylinder.
On the bottom there is a screw, undo that and remove it
Now you can slide the whole assembly out (the plunger with a spring)
*** Look inside the housing, look for any pits or rust spots that ate it up. If the inside of the cylinder is crapped up, then it's buy a master cylinder time.
If the inside of the cylinder is good, then a rebuild should be fine! Goto step 3.
3) Get a rebuild kit! Rallye, ebay or elsewhere.
Looking at that assembly, its pretty obvious what / how to replace. Nothing to it!
Reverse your steps, put it back it, bolt it up, bleed system!
Do the following:
1) Check the cylinder
Remove cap, pump brake watch for back flow (gurgling up, bubbles etc).
If you see no crap bubbling back up and now black crap on the bottom you may only need to bleed the brake system.
If you see back flow, bubbles or sludhe on the bottom, goto step 2.
2) Lets see if it's fragged or rebuild will work.
Get under the dash and disconnect the brake pedal from the master cylinder.
Unbolt the brake like so you can remove the master cylinder.
Now undo the 2 nuts holding the master cylinder on the firewall.
You can lift / remove the master cylinder.
Remove the dust cap (rubber part the brak pedal attaches to.
Using ring pliers or needle nose pliers or even a screw driver, remove the ring under the dust cap inside the cylinder.
On the bottom there is a screw, undo that and remove it
Now you can slide the whole assembly out (the plunger with a spring)
*** Look inside the housing, look for any pits or rust spots that ate it up. If the inside of the cylinder is crapped up, then it's buy a master cylinder time.
If the inside of the cylinder is good, then a rebuild should be fine! Goto step 3.
3) Get a rebuild kit! Rallye, ebay or elsewhere.
Looking at that assembly, its pretty obvious what / how to replace. Nothing to it!
Reverse your steps, put it back it, bolt it up, bleed system!
Re: Brake Fluid Leak
Got it done. Master cylinder is pretty ugly. I order a new cylinder and new brake line. The line snapped like a twig when I was unscrewing it from the cylinder.
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Andy_In_SD
- Posts: 64
- Joined: Sun May 31, 2015 7:21 pm
- Car: 1970 - 2000 5spd Roadster, 1966 SPL311-1600 Roadster
Re: Brake Fluid Leak
Any luck on that or still waiting for parts?
I rebuilt the clutch master cyl on the 66 today, as well as swapping in a new (the right one) intake manifold, carb, linkage etc... Got it idling good. Tomorrow the slave cyl for the clutch, then we see if we can shift....
I rebuilt the clutch master cyl on the 66 today, as well as swapping in a new (the right one) intake manifold, carb, linkage etc... Got it idling good. Tomorrow the slave cyl for the clutch, then we see if we can shift....