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General Brake Question & repair manual

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Mowgli81

Mowgli81

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Apparently the Brakes were done in 2008. The car has sat for the last two years. Upon depressing the brake pedal it goes straight to the floor. I opened the small can that appears to be the "Master Cylinder" filled with brake fluid and it is pretty much empty. I inspected all the brakes at the wheels to see if there was a prominent leak, and I did not see one. I have only worked with more traditional Master cylinders.

My question is this:

1. Can I add brake fluid and bleed them and be OK? Or is there another process I should follow?
2. Is it traditional dot 3 brake fluid?
3. Anyone recommend a good manual for this vehicle?

Thanks to you all for your answers, encouragement and support.
 
1 Bleeding is best be done under presure
2 I think Dot 3 is fine but get the old fluid out (bleed enough)
3 Buy a copy of the Haynes manual as a start. Original manuals are a must too
 
6-cyl Healey brakes are quite conventional. The only things you might find unusual are a) the remote reservoir, which sources fluid for both the brakes and clutch (in concentric sections in the reservoir) and b) the remote servo (booster). The M/C supplies pressure to the servo, which has a small piston which works an atmospheric/vacuum valve that controls the large air/vacuum piston which boosts another (fluid) piston which powers the calipers and slave cylinders (was Rube Goldberg British?).

It'll be hard to help not knowing exactly what was done in 2008, since 'brake jobs' can run the gamut from new pads to new pads, shoes, turned/replaced rotors/drums, etc. The reservoir being dry is a not good sign; there should not be any leaks and brake fluid shouldn't evaporate. It's possible someone left the system dry knowing the car would sit for a while, but that means all the seals may have dried out and may be stuck to the cylinder walls (though being able to push the pedal to the floor indicates at least the M/C is not stuck).

I'd go ahead and fill with DoT 3 or 4, and bleed. If you don't have a pressure rig--I personally have not had much luck with vacuum bleeders--do it the 'old-fashioned way' with someone pumping the pedal while you bleed each wheel. Start with the driver-side rear as it's the farthest from the servo, then do the other rear, then the driver-side front then the passenger front. Flush lots of fluid through and look for crud; if you get clear fluid and a good pedal you're OK. Start the car with your foot putting pressure on the brake pedal and if it goes down an inch or so when the engine fires your servo is OK. Check the clutch action since it shares fluid with the brakes. Bleeding the clutch is conventional but a PITA because the slave cylinder is all but inaccessible. Everyone has their own method, but if nothing else drop the slave cylinder, bleed, then reinstall.

Check for leaks at all wheels, at the M/Cs and under the reservoir. For some reason Big Healey brakes are harder to bleed than other cars; you may well need to bleed again after a few miles.
 
Thank you again BigG and Bob. Your advice is so valuable. I'll give it a shot and let you know. As far as the well being dry I figured it wasn't good. That's a first for me. As far as bleeding goes that's the only way I know how I hated those Sat morn. helping Dad pump-pump-push-pump-pump-push-pump-pump-push. Guess my wife will hate it this evening :smile:

Don't know if this means anything but the clutch seems to work fine. I only say since it appears that these two systems are using the same fluid, That is if I read your post correctly Bob.

GG
 
Mowgli81 said:
...

Don't know if this means anything but the clutch seems to work fine. I only say since it appears that these two systems are using the same fluid, That is if I read your post correctly Bob.

GG
Click to expand...

Yes, they both share the reservoir. The clutch uses the fluid in the tube in the center of the reservoir, the brakes use the fluid in the outer portion of the reservoir. There shouldn't be any leakage between the two, but fluid may slosh over a bit. If both are dry, there must be just enough fluid in the clutch line to actuate the clutch. It'll need to be bled when you fill the reservoir.

Be sure to check for leaks around the M/C and the servo, and around the 4-way junction on the right front fender well.

There is a small gland seal that seals the shaft for the air/vacuum piston in the servo. When it fails the servo will suck brake fluid into the large vacuum cylinder. Your brake fluid will disappear but there won't be any external leaks (note this applies to the stock servo, I'm not familiar with the inner workings of the aftermarket replacements).
 
OK trying to understand this Clutch/Brake fluid thing. If you could let me know if my train of thought here is correct. I see the concentric rings in the "small can" the inner ring was pretty full but the outer ring near empty. I traced a line to a small cylinder/servo then from there to the transmission/clutch. There is a small leak here as the last 6" or so is old flexible line and is dripping. My guess is that is where the fluid is going. The only way I can figure the clutch works and the brakes don't is that the clutch has "priority" and is stealing fluid from the brakes? And/Or the clutch requires so much less to operate properly? I'll continue to look for other leaks but wanted to run this by you guys.

Edit: Bob looks like I might have a failed gland seal? if so what do I replace the gland, servos, large brake cylinder? Hmmmmm Gotta get my haynes manual :smile:

"Bob:There is a small gland seal that seals the shaft for the air/vacuum piston in the servo. When it fails the servo will suck brake fluid into the large vacuum cylinder. Your brake fluid will disappear but there won't be any external leaks (note this applies to the stock servo, I'm not familiar with the inner workings of the aftermarket replacements).

It is very gummed up under there so if you know:
1. What type of hose should replace the aforementioned leaking one? (Is it special or can I build my own?)
2. If special do you know what it is called?
3. Under the care where it connects to the tranny is this where I'd bleed the Clutch?
Thanks in advance! GG
 
re: "I see the concentric rings in the "small can" the inner ring was pretty full but the outer ring near empty."

The clutch has fluid supply, the brakes do not. The brakes leaked their fluid, the clutch did not.

re: "The only way I can figure the clutch works and the brakes don't is that the clutch has "priority" and is stealing fluid from the brakes?"

See above.

1. What type of hose should replace the aforementioned leaking one? (Is it special or can I build my own?)

It's the same as a flexible brake line. Recommend you get familiar with Moss Motors (https://mossmotors.com). There are lots of good suppliers, but Moss is the biggest and a good place to get started. Their catalog is, for all intents and purposes, a parts manual (it's free).


2. If special do you know what it is called?

Clutch flexible line.

https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=28878


3. Under the care where it connects to the tranny is this where I'd bleed the Clutch?

Yep. The bleeder screw is on the top of the slave cylinder. You can remove the transmission cover or pull the two bolts that hold the cylinder to the bellhousing. You might be able to reach the bleeder with a modified end wrench (thinks it's a 7/16" screw), or others have other methods.


Think of the clutch and brake fluid reservoir as being independent supplies that happen to share the same canister. Theoretically, you could use a single supply to supply both, but the risk would be the clutch leaks and you'd lose your brake fluid; and that could be fatal as opposed to losing your clutch, which is just an annoyance.
 
At this point I would replace all the brake and clutch rubber lines. They can collapse on the inside and not be visible from the outside. Be careful when bleeding the aluminum threading can be easily stripped when over tightened. Be sure that the previous fluid was not Dot 5 as it is not compatible with Dot 3 & 4.
 
With some fluid in both compartments in the resevoir, the clutch and brakes should work. After all, there is still a resevoir of fluid for both items, it is just very small in the clutch part. The fact that the line is leaking just outside the clutch slave cylinder is the reson for the loss in the resevoir (naturally).

If you can't get the brakes to work then a number of things could be at fault. Principally the master cylinder is a good starting point, followed by the servo. If the rubbers are gone in the master then that will cause your symtoms. Try bleeding the brake system to see if you can develope some pressure, then see how long it lasts, I had to re rubber my master cylinder following a brake failure, the brakes came up for a week then faded down again, had to buy a new master cylinder in the end.

Can't help with the servo as do not have one.

:cheers:

Bob
 
Follow-up -

I have bleed the brakes and now have good pressure in the lines. Boy was there some nasty coming out of there. All lines are flowing clear and clean. I have yet to test while driving as she is still on the jack stands. I'm still curious where that fluid went. If anything else comes up I'll report. Thank you all.
 
Mowgli81 said:
Follow-up -

I have bleed the brakes and now have good pressure in the lines. Boy was there some nasty coming out of there. All lines are flowing clear and clean. I have yet to test while driving as she is still on the jack stands. I'm still curious where that fluid went. If anything else comes up I'll report. Thank you all.
Click to expand...


If you get a bunch of white smoke out of the exhaust there's a chance the servo ingested the fluid.
 
tahoe healey said:
At this point I would replace all the brake and clutch rubber lines. They can collapse on the inside and not be visible from the outside.
Click to expand...

Here is a cutthrough view of mine. It is not clogged so much as deteriorated.

OldBrakeLine.jpg
 
Hi Greg,

Be aware that your flexible line as shown is so badly deteriorated that I recommend visually checking for wetness or for a white powdery substance developing at the brake cylinders (and calipers as well), especially beyond their rubber components (boots, seals).

Also, you show one flexible brake line. There are three. I bet the other two are in as bad of shape, too. I replaced all of mine and I advise you do the same.

I tend to be easy on certain issues but bad brakes are no laughing matter.

At the very least, make sure your emergency brake is working (as perfect as possible).
 
pkmh said:
Hi Greg,

Be aware that your flexible line as shown is so badly deteriorated that I recommend visually checking for wetness or for a white powdery substance developing at the brake cylinders (and calipers as well), especially beyond their rubber components (boots, seals).

Also, you show one flexible brake line. There are three. I bet the other two are in as bad of shape, too. I replaced all of mine and I advise you do the same.

I tend to be easy on certain issues but bad brakes are no laughing matter.

At the very least, make sure your emergency brake is working (as perfect as possible).
Click to expand...

Just to clarify, the pic above is mine not Greg's. I did replace both caliper lines, but have not done my rear line yet.
 
You guys are awesome! Thanks.
 
Greg,

I'm surprised by some of the posts....re: using Dot 3 fluid? I thought, and maybe I'm wrong here, but if your car has any of the original rubber bits in the braking system, dot 3 will swell them up? I was under the impression that only Dot 4 should be used, like Castrol GT/LMA fluid.

Jerry Rude
 
Lotuswins said:
Greg,

I'm surprised by some of the posts....re: using Dot 3 fluid? I thought, and maybe I'm wrong here, but if your car has any of the original rubber bits in the braking system, dot 3 will swell them up? I was under the impression that only Dot 4 should be used, like Castrol GT/LMA fluid.

Jerry Rude
Click to expand...

Looks like it depends what was originally used (be sure to read all the way to the bottom):

https://www.stoptech.com/technical-support/technical-white-papers/brake-fluid

Anyone know if Healeys came with DoT 3 or 4 (I've been using DoT 5 silicone for years so I don't remember, if I ever knew).
 
Jerry, I think you are thinking of Dot 5. I've always been told you can safely mix Dot 3 and 4 but not 5. I've always used Castrol LMA but it is getting very hard to find. I saw a can on ebay for 12 bucks! I try to buy it when I can at anything below 7 dollars cause you need almost two cans to completely change the fluids and bleed (and it does not store well once opened).
Regardless of your driving mileage, it is something that should be done as part of routine maintenance every two to three years. If you have a leak, it goes both ways. Air gets sucked in and the air will carry moisture.
 
Castrol LMA can be bought on the web for around $15 per 32oz can, enough for a complete flush in my cars.
 
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