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Discussion Starter · #1 ·
So back in June the slave cylinder went out on my 89 convertible. I went ahead and replaced the clutch pressure plate and friction disc, plus I got the flywheel resurfaced. The Saab worked well throughout the Summer and Fall...

Now, she sits in the garage again, with a familiar clear puddle originating under the front of the car. Upon inspection I could literally hear (quite loudly) the seals squishing about in the slave cylinder. It was a Scantech slave from Eeuroparts, and now I've heeded calls to order an OEM slave from TheSaabSite. I'm confident, but not 100% sure that our installation was not the culprit.

Before I accepted that the slave was failing again, my next best guess was that the hydraulic line going from the clutch master cylinder to the slave was leaky. I looked at the flexible rubber part and couldn't tell if the moisture around its connections to the rigid lines were leaky, or just wet from me spilling brake fluid earlier :roll: . I've since removed the line and pressurized it with air, and at least at low pressure the line had no apparent leaks. In fact, when these lines fail, are they explosive and evident, or can they be tiny, hard-to-catch leaks, too? The rubber line is weathered and the metal connectors to the rubber are rusty.

Right now I'm in a preventative maintenance kinda mood and am thinking about replacing this original part. I saw the whole line on TheSaabSite for $60, but because the current line isn't really leaking I didn't wanna buy it. Plus I wouldn't mind getting some brake line fabricating experience. The only tricky part, however, is the flexible rubber part of the line. Where can I get a part like this? Is it possible that I could snag one of the front flexible brake lines (in the wheel well) and use that as my flexible portion, provided I have the right connectors? Based on my research my best luck is ordering online or finding a hotrod/brake shop in town.

If you've had luck with creative solutions in the past, please let me know! :cheesy:
 

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So back in June the slave cylinder went out on my 89 convertible. I went ahead and replaced the clutch pressure plate and friction disc, plus I got the flywheel resurfaced. The Saab worked well throughout the Summer and Fall...

Now, she sits in the garage again, with a familiar clear puddle originating under the front of the car. Upon inspection I could literally hear (quite loudly) the seals squishing about in the slave cylinder. It was a Scantech slave from Eeuroparts, and now I've heeded calls to order an OEM slave from TheSaabSite. I'm confident, but not 100% sure that our installation was not the culprit.

Before I accepted that the slave was failing again, my next best guess was that the hydraulic line going from the clutch master cylinder to the slave was leaky. I looked at the flexible rubber part and couldn't tell if the moisture around its connections to the rigid lines were leaky, or just wet from me spilling brake fluid earlier :roll: . I've since removed the line and pressurized it with air, and at least at low pressure the line had no apparent leaks. In fact, when these lines fail, are they explosive and evident, or can they be tiny, hard-to-catch leaks, too? The rubber line is weathered and the metal connectors to the rubber are rusty.

Right now I'm in a preventative maintenance kinda mood and am thinking about replacing this original part. I saw the whole line on TheSaabSite for $60, but because the current line isn't really leaking I didn't wanna buy it. Plus I wouldn't mind getting some brake line fabricating experience. The only tricky part, however, is the flexible rubber part of the line. Where can I get a part like this? Is it possible that I could snag one of the front flexible brake lines (in the wheel well) and use that as my flexible portion, provided I have the right connectors? Based on my research my best luck is ordering online or finding a hotrod/brake shop in town.

If you've had luck with creative solutions in the past, please let me know! :cheesy:
Get stainless braided hose with AN fittings and braze them on>??? Not sure if AN fittings can cope with pressures in brake setups though....

Otherwise just pay a hydraulic shop to crimp on some new rubber/stainless braided line, might cost you $20 for hose and $50 for work.
 

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I went with the aftermarket insert at a brake shop.........I went originally with a steel braided hose but went back to normal brake flex as subtle engine noise was reflected back through the hose to the chassis....ll.
 

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Ditto Rodent , using a Brake specialist ., the flex section (braided ) now has the advantage of being easily replaced ( comression fittings , nut and tails ) so if it fails again , no need to remove the entire metal line .
Your car is either extremely quiet OR you have sensational ears ! ( mouse like ;ol; )
 

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.....just pay a hydraulic shop to crimp on some new rubber/stainless braided line, might cost you $20 for hose and $50 for work.
Listen to this clever and knowledgeable member.
It could be much cheaper at a place that does tractor repair. There's nothing rare or exotic about the terminal fittings either....It's not Brain Science.
 

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Discussion Starter · #6 · (Edited)
DIY idea...

Get stainless braided hose with AN fittings and braze them on>??? Not sure if AN fittings can cope with pressures in brake setups though....
Yeah, I found this hose online, but as you said it has -3 AN fittings (SAE thread size 3/8-24). And the clutch line fittings on the ends of the clutch line are M10 x 1, I think.

Here are my thoughts on using a wheel well to caliper brake hose for the flexible part, using parts from Autozone: I run a few feet of rigid line from the master to the front of the car. The rigid line will terminate at a union around the air filter housing, and one end of a rear brake hose will connect to that union. On the other end of the hose another union will be connected. And finally, on the other end of that second union is a very short length of brake line that will plug into the slave cylinder. In total, the parts would cost $30, plus I'd have the satisfaction of having done it myself, which I always consider very valuable! :cheesy:

Also, thanks to Jim, Aussie, and Rodent for the advice. I'm not sure if my brake hose idea would be practical, but I wanted to run it by you guys anyway. :)
 

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Your car is either extremely quiet OR you have sensational ears ! ( mouse like ;ol; )
....not really......it's just me chasing a bug-bear noise..............the 5dr exhibits an odd oscillation type noise when the clutch is exercised.....and which generally not evident or prominent when cold.
I've changed the entire components in the clutch, pressure plate, disc, hydraulics, slave, thrust bearing......even changed the input shaft chasing this noise.
The flex line did make some difference in the noise reflected back into the chassis........
Mrs Rodent was the first to comment about it........and she generally doesn't take any notice of noises, smoke, steam.......speed humps, bumper bars, other cars..........
 

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Yeah, I found this hose online, but as you said it has -3 AN fittings (SAE thread size 3/8-24). And the clutch line fittings on the ends of the clutch line are M10 x 1, I think.

Here are my thoughts on using a wheel well to caliper brake hose for the flexible part, using parts from Autozone: I run a few feet of rigid line from the master to the front of the car. The rigid line will terminate at a union around the air filter housing, and one end of a rear brake hose will connect to that union. On the other end of the hose another union will be connected. And finally, on the other end of that second union is a very short length of brake line that will plug into the slave cylinder. In total, the parts would cost $30, plus I'd have the satisfaction of having done it myself, which I always consider very valuable! :cheesy:

Also, thanks to Jim, Aussie, and Rodent for the advice. I'm not sure if my brake hose idea would be practical, but I wanted to run it by you guys anyway. :)
Read up on installing true AN hose fittings (It is not hard and can be done in a 4" vise). I used to assemble them as part of a mod on an aircraft and in the sizes we would use it is very easy. However if you want to go to compression type fittings, MS series is rated to 3,000 PSI normal and are also available from places like Aircraft Spruce. AN fittings are threaded in and brazing would be ridiculous, not to mention leaky. Biggest tip would be to have a piece of rod that can fit through the nut side and a plug to secure the nut for the install. If online the Aviation Maintenance Technician general book AC 43.13-1b section 9 has a good illustration of the process and related pieces.
 

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....not really......it's just me chasing a bug-bear noise..............the 5dr exhibits an odd oscillation type noise when the clutch is exercised....
Exercised?
Some noises like that come from worn main bearings. It's always hard to localise main bearing noises. 'Exercising' the clutch also means temporarily eliminating/loading crankshaft end-float.
They can make noise for years without causing any real problems.....Sometimes they don't.

Remember that internet advice about subtle noises is not an exact science.
 

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Discussion Starter · #10 ·
Clutch Line Size

So I looked at my plans again and I realized that connectors and tubing on the clutch line are definitely larger than the brake lines, meaning the M10 x 1 connectors on the brake hose (and the hose's diameter) are too small for this application. With this fact in mind a trip to the brake shop just became much more likely. ;oops:

So, is this clutch line 1/4" or 6mm? I've eyed it very carefully for a while and just can't tell. The fittings definitely seem like they're M12 x 1, but I'm just not positive on the tubing.
 

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Swedish cars started in Imperial measurement, moved to SAE and then switched to metric. The switches weren't always seamless, the lower front shock mount nut is a perfect example. I'd guess the clutch line is SAE, but it's just a guess. Best to match it up in person.
Thank the Good Lord they seemed to have avoided Whitworth for the most part (except what leaked in through Triumph).
 

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Discussion Starter · #12 ·
Swedish cars started in Imperial measurement, moved to SAE and then switched to metric. The switches weren't always seamless, the lower front shock mount nut is a perfect example. I'd guess the clutch line is SAE, but it's just a guess. Best to match it up in person.
Thank the Good Lord they seemed to have avoided Whitworth for the most part (except what leaked in through Triumph).
Here's another thought: On some non-Saab/racing forums people said they've replaced their 1/4'' clutch line with more common 3/16" line without any issues. The only thing that would worry me is decreased fluid volume to the slave cylinder (and perhaps stressing the clutch master, too). But if I could use 3/16" tubing, then I could just buy two M12 male to M10 female adapters from Autozone. Is that doable?
 

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Short answer: don't worry.
The laws of physics say you can use any size line you want if it's not too small for the rate of fluid transfer. It's the ratio of master cylinder diameter to slave that's critical. You could use a 1" line if you wanted.
 

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Discussion Starter · #14 ·
Oh!

Thanks Jim, your post reminded me how much I've missed Pascal's Principle in Physics... kinda. :lol:

Here's another thought, though (and perhaps an opportunity for another Physics refresher): On my truck, the brake lines under the reservoir are coiled about three times to make them more flexible. I can even pinch them together with my fingers and they're pretty durable and springy. Would coiling the clutch line from the bottom of the engine bay to the top of the slave cylinder provide similar vibration protection without having to use a rubber hose? A springy clutch hose, in effect?

Some forums say it's doable, while others say the engine vibrations are simply too overwhelming that close to the slave. I think it could probably work, but it depends: does the engine really get shaken around enough to stretch/stress a few coils of line to the point of rupturing?
 

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You're not just dealing with engine vibration. You also have to account for the engines twisting (especially as the mounts wear...) and I think it is this repeated twisting stress that requires a flexible section of line. With your truck no part of the hard line is subjected to (this level of) twisting motion.

And with the post '86 (at least) 900's the clutch line is metric thread.
 

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I was just a dealership mechanic, not an engineer, however......
The constant movement of the power unit relative to the chassis would soon fatigue a metal line, coiled or not. Remember that on your truck the master cylinder is mounted solidly but the connections to the moving parts (axles/wheels) is by rubber lines. Some of the coiling on your truck is to adapt standard length lines to 'this year's' models for reasons of production cost.
My free advice (remember what you paid for it if I'm wrong) is to preserve a rubber hose type connection.
 

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Discussion Starter · #17 ·
Before the Buy...

Alright, so here's my plan as of now:

1. Clutch Master to a few feet of M12 6mm line,
2. M12 line to M12 female/M10 male adapter,
3. M12 female/M10 male adapter to M10 union,
4. M10 union to brake hose,
5. Brake hose to M10 union,
6. M10 union to M12 female adapter/M10 male adapter,
7. Short length of M12 6mm line to slave.

Another idea I had was to just put the M12 female/M10 male adapters at each end (at the master and the slave) and just run 3/16" line all the way down. However, as we all know there's not much working room at the MC. Is one setup really any better than the other?
 

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Exercised?
Some noises like that come from worn main bearings. It's always hard to localise main bearing noises. 'Exercising' the clutch also means temporarily eliminating/loading crankshaft end-float.
They can make noise for years without causing any real problems.....Sometimes they don't.

Remember that internet advice about subtle noises is not an exact science.
Thanks Jim.
The noise at first instance would seem to be a noisy thrust bearing but, I now have 3 thrust bearings (ex this car) on the bench that I have changed in sympathy with all the other clutch work that the 5dr has demanded over the last 12 months.......slave, line/flex, oil leaks, etc.
I really didn't think all these bearings could be end of life so quick but being a backyard hack, I would be the first to acknowledge that a work practice I may have applied in working in the engine bay may have created the noise from some other action or side effect.
The comparison, the vert, does not present the same 'noise'......I agree this is not a fair comparison as the two cars have different milage and different histories.
As I commented earlier, I admit I'm chasing a personal nuisance, something not worthy......something that's more likely to be mental utopian desire to silence the noise.
 

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If the hard line is not corroded/cracked/kinked, why not just cut outside of crimp fittings and install compression fittings to the tube side and fabricate the interior line to mate to a compression to flare union?
 

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SNIP...
As I commented earlier, I admit I'm chasing a personal nuisance, something not worthy......something that's more likely to be mental utopian desire to silence the noise.
Can you reccord your gremlin (sound) and post on Youtube?
 
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