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  1. #11
    Saab Fan
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    16 Mar 2012
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    Vancouver BC
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    22
    Saab(s)
    1989T conv airflow, 1987 SPG, 1990 900s, 1991 4dr
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    Euromobile.

    There is any other caliper with Fron hand brake that will fit in a pre 88 c900 ?

    Do you think that well maintained pre 88 callipers are comparable with 88+ callipers ?

    I'm asking this because my spg is just not right when braking and I have the parts to change it to 88+ callipers but maybe is just bad adjustment or something else but compared with the braking power of my 1990 900s there is a world of difference.

    Thanks.

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  2. #12
    Edward G
    Saab Enthusiast
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    10 Mar 2011
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    Victoria Australia
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    121
    Saab(s)
    T5.5 84 900T8
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    Quote Originally Posted by jamengual View Post
    Euromobile.

    There is any other caliper with Fron hand brake that will fit in a pre 88 c900 ?

    Do you think that well maintained pre 88 callipers are comparable with 88+ callipers ?

    I'm asking this because my spg is just not right when braking and I have the parts to change it to 88+ callipers but maybe is just bad adjustment or something else but compared with the braking power of my 1990 900s there is a world of difference.

    Thanks.
    I've driven both types, and a friend who has driven both for extended periods agrees, there is negligible difference between early and late style brakes. Later style rotors are way more expensive.

    The pads are slightly easier to change in later brakes.

    Are you sure your brake booster isn't toast? Is there air in the brake lines? If your pedal is spongy then air is to blame. Old brake fluid has water in it and can make your braking effort poor.

    Test brake booster with 3 steps.
    engine off - press brake pedal several times quickly, with each subsequent pump pedal travel should decrease
    engine off - press brake pedal firmly in once and hold, start engine, brake pedal should sink considerably
    engine on - press brake pedal in firmly and hold, turn engine off, brake pedal should not move (sink or rise) for 45 seconds.

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  3. #13
    Renato Piereck
    Spreading the Saab virus rpiereck's Avatar
    Join Date
    24 Jul 2011
    Location
    Ansbach, Germany
    Posts
    1,524
    Saab(s)
    '00 9-5 Aero SC, 87 900i 8v
    Thumbs Up:   2
    Doing my brakes today I found out the right side piston is seized and won't move. I was able to screw in the piston on the outer side, but the inner side won't budge. Is it always the handbrake mechanism that seizes? I have never rebuilt a brake caliper, do you recommend me doing the job myself or replacing the whole caliper?

    Is this the kit I need to rebuild it? http://www.skandix.de/en/spare-parts...-axle/1002976/

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    Now: '00 Saab 9-5 Aero Combi - '89 Peugeot 205 CTI - '91 Peugeot 309 GTI
    Gone: '87 Saab 900i - '95 Saab 900 SE Turbo

  4. #14
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
    Join Date
    14 Aug 2010
    Location
    Medford, MA
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    683
    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    That kit supplies most of the necessary seals. It's missing one, that only comes in the genuine Girling kits. I've reused that one before and it's usually fine. The problem is that, if your piston is frozen, it is probably rusty. I would take the caliper off, plug the line, and remove the pistons to see. The inner piston should not turn, only slide back and forth. It may just be stiff or covered in brake fluid residue "varnish". Any rust where the piston meets the seal, and you're going to have to buy a "rebuilt" caliper anyway. These always come with new pistons, but the sliding yokes are often loose-fitting and worn.

    Was the outer pad much thinner than the inner pad on the side where you could not move the inner piston? This would be a fairly definitive sign that things are sticking inside the caliper. Even if this is the case, you still need to dismantle to find the difference between rust and varnish.

    So, your plan:
    1. Take caliper off, remove both pistons carefully using screwdriver and pliers for leverage
    2.a. If pistons rusty, buy "rebuilt" caliper and assemble new caliper out of best parts from "rebuilt" one and your original one.
    2.b. If pistons not rusty, buy seal kit from Skandix and re-assemble per my tutorial. Use a scouring pad (not steel wool) to remove any brake fluid residue "varnish" from the pistons before re-inserting.

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    Last edited by euromobile900; 05 August 2013 at 14:42.
    Ask me a question about your c900! I promise I either can answer it or know someone who can

  5. #15
    Edward G
    Saab Enthusiast
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    10 Mar 2011
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    Victoria Australia
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    121
    Saab(s)
    T5.5 84 900T8
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    Hey just an update to anyone interested

    Centric and Lucas are selling caliper pistons loosely for pre and post facelift brakes - both front (inner/out) and rear pistons are available at rockauto.com, relatively expensive compared to a rebuilt caliper (but the shipping cost is where the $ go up)

    This is great news for people wanting to overhaul their brakes themselves.

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  6. #16

    Join Date
    05 Jan 2015
    Location
    Netherlands
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    1
    Saab(s)
    900 GLE 1980
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    I'm currently rebuilding my front calipers of my 1980 900 GLE.
    I have found your tutorial very useful and thank you for the effort of ducumenting this. I have a few questions though and my feeling is that euromobile900 knows the answers.

    The backcaliper (that has the handbrakemechanism in it) has a chamber with two holes on each side. One is where the handbrake pivotpin goes in from the outside, the other hole is the one where the shaft goes through that pushes the front caliper against the inner pad and so activating the handbrake. When braking with the brakepedal fluid is pushed against either calipers and so building up pressure in the space between the inner and outer caliper.

    Fluid can be squeezed into the chamber through the hole even though the hole has the little shaft running through it, it is not sealed. So brakepressure will also be build up in this chamber where it is only blocked from going out of the caliper by the 2 o-rings that surround the handbrake pivotpin.

    You advise to fill the chamber with brakecaliper grease but that stuff has a realy high viscosity and is very difficult to get in.

    Questions
    1: Will brakefluid be squeezed through the pivotpinhole once it gets inside the chamber?
    2: If air is trapped inside the chamber will that lead to a spongy feel in the brakepedal?
    3: What is a new or professionally rebuild caliper filled with?

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  7. #17

    Join Date
    26 May 2015
    Location
    United States
    Posts
    1
    Saab(s)
    1985 Saab 900s 3-door; 1985 Saab 900S Sedan
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    Great tutorial that I wish I'd had for my brake rebuild in the pre-internet days. I'm hoping you know the answer to this: Why the Yoke?!
    I'm actually writing about my Saab as part of a book, including the story of how I neglected to adjust the handbrake cable, dragged my brakes, gave up in a fit, and replaced the whole assembly with rebuilt brakes only to forever be reminded of my sins with the dreaded clunk.
    What I cannot figure out now is why they used this absurd yoke system, which they must have realized was a mistake when they replaced it with a more conventional solution soon after.
    So, why the yoke in the first place??

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  8. #18
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
    Join Date
    14 Aug 2010
    Location
    Medford, MA
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    683
    Saab(s)
    '90 900 LPT with a flat-nose conversion
    Thumbs Up:   2
    Olav PM'd me the question and I responded there. Here is my response, for posterity.
    Quote Originally Posted by Olav
    The backcaliper (that has the handbrakemechanism in it) has a chamber with two holes on each side. One is where the handbrake pivotpin goes in from the outside, the other hole is the one where the shaft goes through that pushes the front caliper against the inner pad and so activating the handbrake. When braking with the brakepedal fluid is pushed against either calipers and so building up pressure in the space between the inner and outer caliper.
    Correct.

    Fluid can be squeezed into the chamber through the hole even though the hole has the little shaft running through it, it is not sealed. So brakepressure will also be build up in this chamber where it is only blocked from going out of the caliper by the 2 o-rings that surround the handbrake pivotpin.

    Brake fluid should be blocked from entering the chamber through the hole. The hole should have a rubber seal on it that seals against the shaft and prevents brake fluid from entering. The seal sits in a groove in the hole. The seal is similar to a very fat O-ring. If it's not there or is leaking, you will need to find a new one. Also, if the shaft is rusted, you will need to use sandpaper to remove the rust and make it smooth so that it seals. If it is badly rusted, it is possible you may need to replace it. If it does not seal, you will have a big leak.

    You advise to fill the chamber with brakecaliper grease but that stuff has a realy high viscosity and is very difficult to get in.
    You don't need to fill it completely. A few mL will work.


    1: Will brakefluid be squeezed through the pivotpinhole once it gets inside the chamber?

    It should not go through the shaft hole into the chamber. If it does, you probably need a rubber seal there. If fluid does enter the chamber under pressure, I imagine that it would be squeezed through the pivot pin hole.

    2: If air is trapped inside the chamber will that lead to a spongy feel in the brakepedal?

    Fluid should not enter the chamber, so it is OK to have some air in there.

    3: What is a new or professionally rebuild caliper filled with?
    There is generally a small amount of brake caliper grease inside the chamber of a professionally-rebuilt caliper. It is usually not enough, which is why they get stuck so frequently.

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    Ask me a question about your c900! I promise I either can answer it or know someone who can

  9. #19
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
    Join Date
    14 Aug 2010
    Location
    Medford, MA
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    683
    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    Quote Originally Posted by exchaoordo View Post
    Great tutorial that I wish I'd had for my brake rebuild in the pre-internet days. I'm hoping you know the answer to this: Why the Yoke?!
    I'm actually writing about my Saab as part of a book, including the story of how I neglected to adjust the handbrake cable, dragged my brakes, gave up in a fit, and replaced the whole assembly with rebuilt brakes only to forever be reminded of my sins with the dreaded clunk.
    What I cannot figure out now is why they used this absurd yoke system, which they must have realized was a mistake when they replaced it with a more conventional solution soon after.
    So, why the yoke in the first place??
    Sliding yoke calipers aren't just on Saabs. They are an older design that was common on a lot of cars in the '60s and '70s as disc brakes moved past their infancy and into the mainstream. I think it might be fair to say that older designs are higher-maintenance, but feel better and are more solid when they do work right, and also last longer if they're taken care of. Take for example a table saw from the '50s versus one made now. You will have to oil the '50s table saw, but it will last much longer and is better made. The newer calipers are equipped with a slide mechanism, but it is made of throw-away items. Instead of metal-on-metal, they have rubber bushings, which you have to replace. They don't clunk when they're worn out - they become misaligned and drag and squeak and overheat and warp the discs. It all depends what you're after. Do you want a car that's maintenance free, but then you have to replace everything at 150,000? Or do you want one you have to grease periodically, but will last 500,000 miles? The yoke system may not be so absurd when you look at it from this perspective.

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    Ask me a question about your c900! I promise I either can answer it or know someone who can

  10. #20
    Geoff

    Join Date
    27 Feb 2019
    Location
    London, UK
    Posts
    1
    Saab(s)
    Saab 96v4 1971, Saab 96v4 1972, Saab C900 Turbo 1986, Saab 9-3 Aero Vert 2004, Saab 9-3 SS TTid 2012
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    New pistons are available as per previous post from eBay (at least in Europe).
    I have bought two kits in preparation of and complete rebuild of the brakes for a 1986 900 8V Turbo. It had been standing in a barn for 9 years as a non-runner.
    You never mentioned how to remove the self-adjusting mechanism for the outside piston, and how to fit the self-adjusting mechanism back into the new piston.
    Having finally removed the self-adjusting mechanism from the piston, I can now work out how it is connected.
    The self-adjusting mechanism is held in placed by 8 points, around the circumference of the self-adjusting mechanism, by deforming the piston at those points, thereby clamping the self-adjusting mechanism in place.
    As I do not have a multi ton press with an 8 pointed tool to crimp in the self-adjusting mechanism, any ideas on how to fit it?

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