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 Front Brake calipers - very tight to move.
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andydeans3
V4 Guru

United Kingdom
1994 Posts

Posted - 21 Jun 2020 :  19:18:40 Show Profile Reply with Quote
I'm in the process of replacing my front discs, and of course took the mechanical part of the calipers off to clean/grease them up around the pivot pin, to make sure that they move easily.

I didn't touch the hydraulics. Piston that was protruding, looked clean, and after applying some brake fluid, went back easily into the cylinder.
Calipers were new in 2016. (65 000 kms/40 000 miles ago)

Caliper mechanicals working well, moving nicely, UNTIL, I locate the sliding part under the spring loaded plate at the top. ie the normal position when fitted to the car.
Then it gets very tight to move. (ie once back on the car a good sized mallet is required, to move the caliper back and forth).
It's as if the gap under the spring is too small for the "tongue", that slides under there. The spring loaded pin doesn't appear to have any adjustment on it.
Perhaps this is normal?
Should I file the "tongue" down a bit, so that it slip and slides nicely under the spring loaded pin?

Any input appreciated, before I finish the job tomorrow.

ps the discs were seriously corroded on the inside, but not on the outside. The pads look to be evenly worn, both sides.
These discs were fitted in 2016, and have done about 65 000kms/40 000 miles.


1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro

Edited by - andydeans3 on 21 Jun 2020 23:03:22

Woody
V4 Guru

United Kingdom
2758 Posts

Posted - 22 Jun 2020 :  15:45:44 Show Profile Reply with Quote
Your description suggests the top hat inside the spring has seized on the top fixed pin and needs soaking to release. The fact it has seized is causing the tightness. You shouldn't need to file anything if it gets released.
It might be an idea to have the caliper Halves de-rusted with wire wheel or even bead blasted, then painted. Use copper grease at the sliding points.
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andydeans3
V4 Guru

United Kingdom
1994 Posts

Posted - 22 Jun 2020 :  16:34:23 Show Profile Reply with Quote
Woody.
The spring's not siezed. Everything is slipping and sliding nicely, until you push the tongue under the spring loaded plate. Then it becomes very tight.
I'm going now to take the whole assembly off again, to have a closer look.
Having taken it all apart again I can confirm that the spring is completely compressed, but does not "uncompress", so to say.
The whole pin assembly and spring is free to turn.
On the back side of the plate, (opposite the spring), the pin just seems to have been "mushroomed" with a hammer to keep it in place.
Seems a bit agricultural!!

Am I correct in assuming that the whole assembly should swing back and forward easily, even when the tongue is under the spring loaded plate?

One more question.
The bolts that hold the assembly on to the hub assembly. Copper Grease or Locktite?

Photos below.

Free to swing!
[/url

Still free to swing.
[/url
OOO getting tight!

[/url]

Need a mallet now.
[/url]

Mallet time!
[/url]

Spring detail.
[/url]

1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro

Edited by - andydeans3 on 22 Jun 2020 17:37:04
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Woody
V4 Guru

United Kingdom
2758 Posts

Posted - 23 Jun 2020 :  00:36:01 Show Profile Reply with Quote
You can see the top hat brim between the spring and the L shaped bracket. You should be able to put a screwdriver under the L bracket and lever against the spring. I shall try to get a movie of my spare caliper in the garage to demonstrate tomorrow.
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GeoffC
V4 Mad

United Kingdom
507 Posts

Posted - 23 Jun 2020 :  11:00:52 Show Profile Reply with Quote
Andy you should have a metal shim under the fixing to hub bolts which you then hammer onto the bolt head side to prevent them from coming loose. If not use Loctite as that's the modern way. Definitely don't want them coming loose, happened to me on a rally once!
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andydeans3
V4 Guru

United Kingdom
1994 Posts

Posted - 23 Jun 2020 :  12:05:25 Show Profile Reply with Quote
Geoff. Oooo, thats doesn't sound good.
There is a locking washer to fold up against the bolt, to theoretically stop the bolt coming undone.
I'll use some loctite as well.
Belts and braces mate, belts and braces.

Woody.
That would be great if you could post a short movie.
I should say that the spring is compressed, and just stays there. Both calipers.
Since this pin/spring assembly seems to be just fitted to the caliper by way of the pin being simply mushroomed over on the back side, not easy to remove/replace.



1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro
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christophe
V4 Fanatic

France
224 Posts

Posted - 23 Jun 2020 :  13:50:33 Show Profile Reply with Quote
Yes, the spring looks like it is already fully compressed without the pressure of the moving part.
I would replace the pin with a correct one or cut a spire from the spring.
Best of luck for this one and thanks for the detailed pictures.
Nice day to all.

Edited by - christophe on 23 Jun 2020 14:34:08
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deggsie
V4 Fanatic

United Kingdom
431 Posts

Posted - 23 Jun 2020 :  17:05:18 Show Profile Reply with Quote
Andy
Another vote for the spring too long - see photos on UKS.
Derek

___________________________
Saab - beyond the conventional !
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andydeans3
V4 Guru

United Kingdom
1994 Posts

Posted - 23 Jun 2020 :  19:36:03 Show Profile Reply with Quote
Deggsie
Saw your photos across on the UKSAABS site.
Very nice!

Christophe.
I doubt if the spring and pin are available as spare parts. Also the pin is fixed to the plate by simply being "mushroomed" over with a hammer, on the back side. Obviously I could drill it out, but I'd need a new pin then.

I have now in fact filed the plate that goes under the spring, a little, and it is sliding better now. Just needs a good dunt with the hand, (coup de main), to make it move, rather than having to use a mallet.
That'll do for the moment.
I'll do the other side tomorrow, which has the same issue.


1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro

Edited by - andydeans3 on 23 Jun 2020 19:39:42
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Woody
V4 Guru

United Kingdom
2758 Posts

Posted - 23 Jun 2020 :  23:12:50 Show Profile Reply with Quote
I didn't get to find the spare caliper today. Will try again tomorrow. Will also check the height of the pin.
Here is an older photo to show the pin and spring at rest. I am wondering if your pin has been removed in the past and shortened. Have you checked it against the other side?
I shall post the video on Facebook.


Edited by - Woody on 23 Jun 2020 23:15:45
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christophe
V4 Fanatic

France
224 Posts

Posted - 23 Jun 2020 :  23:22:02 Show Profile Reply with Quote
quote:

Christophe.
I doubt if the spring and pin are available as spare parts. Also the pin is fixed to the plate by simply being "mushroomed" over with a hammer, on the back side. Obviously I could drill it out, but I'd need a new pin then.

I have now in fact filed the plate that goes under the spring, a little, and it is sliding better now. Just needs a good dunt with the hand, (coup de main), to make it move, rather than having to use a mallet.
That'll do for the moment.
I'll do the other side tomorrow, which has the same issue.



I thought the parts shown in my reply were the right replacement parts. I will investigate this further as some noise is coming from my right caliper when going backwards. I also thought about filing the plate as you did, but as the spring can't act normally when being always compressed, I wonder if you'll get satisfactory results.
Night night to all
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Woody
V4 Guru

United Kingdom
2758 Posts

Posted - 23 Jun 2020 :  23:35:56 Show Profile Reply with Quote
Hi Christophe, What sort of noise are you getting when you are reversing?
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deggsie
V4 Fanatic

United Kingdom
431 Posts

Posted - 24 Jun 2020 :  09:46:51 Show Profile Reply with Quote
quote:
Originally posted by andydeans3
I doubt if the spring and pin are available as spare parts ...

Andy
Christophe's photo was from the Skandix site, which is showing repair kits available, see https://www.skandix.de/en/spare-parts/brakes/brake-calipers/repair-kit-brake-caliper-guide-bolts-front-axle-for-one-brake-caliper/1067791/
Derek

___________________________
Saab - beyond the conventional !
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andydeans3
V4 Guru

United Kingdom
1994 Posts

Posted - 24 Jun 2020 :  10:07:55 Show Profile Reply with Quote
Christophe/Woody/Deggsie.

Thanks for all the info.

Woody.
Both pins are the same. Same spring, same issue.
Which Facebook page are you referring to?

I will order a pair of these assemblies, and have a go at replacing them.
If I have new assemblies, I don't mind drilling out the old pins.
Drilling out is the only way I can see of removing them.

in the short term, filing the plates will do.
Thanks for all your input guys.

Deggsie
I'm away up to Aberdeen in the next few days to see how Stig is getting on with his 96 project.
Andy


1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro
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Derek
V4 Guru

United Kingdom
2187 Posts

Posted - 24 Jun 2020 :  10:15:34 Show Profile Reply with Quote
"Callipers were new in 2016." New as in reconditioned? Pin may have been reused. The original peened over material removed when taking out the pin or afterwards. Fitting and peening it over again would make it shorter and so over compress even a new spring. No easy way out other than a new pin/repair kit. Someone with a lathe could produce a batch of these pins for very little money.
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christophe
V4 Fanatic

France
224 Posts

Posted - 24 Jun 2020 :  10:22:01 Show Profile Reply with Quote
quote:
Originally posted by Woody
Hi Christophe, What sort of noise are you getting when you are reversing?



Hello Woody,
I usually get a slight clunk from the front right wheel. Also, the brakes tend to screech a little when hot. They are working perfectly otherwise. I know I also have to replace the brake hoses, so a dismantling is in the future. This brake setup with wedged brake pads was a new one to me. I never saw this one before.
Nice day to all.
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