Standard vs. performance brake pads

[mikeloadsasaabs]

SWMBO is giving me earache about the squealing from the DS2500 front pads. I've done all the usual things with copaslip etc. but it doesn't help. I'm thinking about switching back to standard pads to stop the noise, in both senses  .

The reason I went to higher performance pad stems from a nasty experience with brake fade on standard Saab pads some years ago on my old 9-5. Since then I haven't trusted them on the front of the Aero. The last time I changed the pads a couple of months ago, I tried to get hold of some Mintex M1144s because they are reputed to have less of a problem with squealing, but although I could find them advertised, no-one actually had them in stock, nor a realistic timescale for getting hold of them.

The DS2500s are fine, but with a lot of slow speed and town use they don't often get warmed up enough not to squeal. However, there are occasions when we charge up and down mountains for extended periods, and I'm reluctant to change back to standard pads.

My question is, has anyone actually experienced any fade worth talking about on standard pads recently? And how about the general performance of them?

[Audax]

My question is, has anyone actually experienced any fade worth talking about on standard pads recently? And how about the general performance of them?

I've never had a problem with fade on standard Saab brake pads, I'd be interested to know if this was a problem on a track or coming down a mountain? Was it that the brake fluid started boiling and did you have the fluid checked for moisture at that time?

[mikeloadsasaabs]

I've never had a problem with fade on standard Saab brake pads, I'd be interested to know if this was a problem on a track or coming down a mountain? Was it that the brake fluid started boiling and did you have the fluid checked for moisture at that time?

TBH it was some time ago. We'd driven over a mountain pass, and were descending the other side. It never happened again so I didn't bother with any proper diagnosis, but it concerned me at the time. I always change the brake fluid every other year as a matter of course (or more accurately, I pay the garage to do it).

We've travelled the Grossglockner High Alpine Road twice this year without issues which is a pretty good test! It's a must if you are in Austria....

[sgould]

One of the reasons that I went for the big Hirsch brakes on the 2002 9-5 Aero saloon, was that the brakes felt weak in the Alps.  My wife was also the one who wanted better brakes.  The 2002 set were the 4-pot Brembo ones, and when warmed up, they were very good, but probably not worth the expense.


The ones I have on the current car are the 345mm single piston calliper ones.  My wife told me to put them on the replacement car too!  They are very good and the Ferodo DS2500 on those brakes have never squeaked, even with a lot of low speed work when spend days just driving locally.  I have replaced them with the Mintex M1144 and they are just bedded in and seem fine too with no squeals.

The are Pagid pads around as well as OE.  I have used both before the Hirsch upgrade and I didn't notice a difference.  Neither worked without a hard push at speed, which my wife felt was too much.

I suppose that I have to mention EBC Yellowstuff pads.  But my experience with other EBC products has been poor and I wouldn't use their brake parts on any car I own.

[sgould]

According to the Mintex Brake book, you can fit either MBD1813 or MDB2317 pads to the front of a standard Saab 9-5.  The only difference seems to be the MDB2317 have the wear indicator.

Mintex Book link: http://www.brakebook.com/bb/mintex/en_US/applicationSearch.xhtml

Camskill list them: http://www.camskill.co.uk/m33b0s3361p27446/Mintex_Performance_Brake_Pads_Mintex_M1144_-_MDB1813M1144_-_Mintex_Racing_Brake_Pads_

[mikeloadsasaabs]

Hmm, interesting develoment on the squeaky brakes! SWMBO went to Berchtesgaden with a friend to visit the Christmas market yesterday. On the way back, she had a bit of a brainstorm and couldn't remember the route home, so she stopped to ask a policeman the way. He had a quiet word with her and suggested that she should take the car to a garage to get the brake squeal sorted, as there was the distinct possibility that we might get pulled over for having faulty brakes. Now, I know quite well they are in good working order having had new pads all round over the last three months, but I don't really want to get into an argument about their condition, nor debate the road legality of DS2500s. So it looks like going back to standard pads.

[Mark B]

Mike,

telling the difference between the two sorts of brake fade is easy.  If the pedal goes spongy and then to the floor, your brake fluid is old and the water vapour dissolved in it has boiled.  If you exceed the working temperature of the pad material and its coefficient of friction drops off, you need to press ever harder on the pedal to have the same retardation, but this is usually accompanied by some obvious very hot brake smells, smoke coming out of the wheel arches when you stop etc.

The DS2500 pad is good for two reasons: 1. it is tolerant of high temperatures and 2. it has a high (and constant) coefficient of friction so you need less force on the pedal than with standard pads.

In my experience, the M1144 material is nothing like as good as DS2500.

You might want to have a chat with Alyn at AS Performance 0191 410 3770 who is very knowledgeable.  I was looking for some DS2500 pads for another car recently but they were rather expensive.  Alyn told me that Brembo had recently introduced a product which was benchmarked against the DS2500 but it is being marketed at a lower price.  He may well know about whether it is less likely to squeal.  Oddly enough, my DS2500 pads (9-5 Aero brakes on a 9000) have never squealled.

Brake squeal is caused by the pad vibrating.  Some make of pads (M1144 from memory) come with a stick on pad which is supposed to stop squeal.  I think 3M make a product which is widely available on-line, or I may even have some Mintex stick on pads lurking in my garage that you could have.  Many companies (Wurth, Bosch, LiquiMoly etc) sell anti squeal grease/paste/goo.  I feel sure that trying the stick on pads would be worth while.  See here http://www.ebay.co.uk/itm/Brake-Pad-Anti-Squeal-backing-pads-3M-x4-ASK1-/191314514764

Was the quietly spoken police officer of the German or Austrian type?

[mikeloadsasaabs]

Mike,

telling the difference between the two sorts of brake fade is easy.  If the pedal goes spongy and then to the floor, your brake fluid is old and the water vapour dissolved in it has boiled.  If you exceed the working temperature of the pad material and its coefficient of friction drops off, you need to press ever harder on the pedal to have the same retardation, but this is usually accompanied by some obvious very hot brake smells, smoke coming out of the wheel arches when you stop etc.

The DS2500 pad is good for two reasons: 1. it is tolerant of high temperatures and 2. it has a high (and constant) coefficient of friction so you need less force on the pedal than with standard pads.

In my experience, the M1144 material is nothing like as good as DS2500.

The fade I had was definitely pad-related. For years I've had the fluid replaced at every other MOT, thus ensuring that it's never more than 2 years old. And it's just been changed this time as well.

You might want to have a chat with Alyn at AS Performance 0191 410 3770 who is very knowledgeable.  I was looking for some DS2500 pads for another car recently but they were rather expensive.  Alyn told me that Brembo had recently introduced a product which was benchmarked against the DS2500 but it is being marketed at a lower price.  He may well know about whether it is less likely to squeal.  Oddly enough, my DS2500 pads (9-5 Aero brakes on a 9000) have never squealled.

I've always had squeal from the two previous sets of DS2500s I've had, whether fitted with new discs or existing ones. When I lived in the UK I always bought my pads from Alyn, but for some reason I didn't this time and I can't remember why - perhaps they weren't in stock, or maybe he doesn't deliver outside the UK.

Brake squeal is caused by the pad vibrating.  Some make of pads (M1144 from memory) come with a stick on pad which is supposed to stop squeal.  I think 3M make a product which is widely available on-line, or I may even have some Mintex stick on pads lurking in my garage that you could have.  Many companies (Wurth, Bosch, LiquiMoly etc) sell anti squeal grease/paste/goo.  I feel sure that trying the stick on pads would be worth while.  See here http://www.ebay.co.uk/itm/Brake-Pad-Anti-Squeal-backing-pads-3M-x4-ASK1-/191314514764

Whenever I reassemble the brakes, I always copaslip the back of the pads. I'll take a look at the anti.squeal pad option though, and thanks for the offer of the stick-on pads,thank you.

Was the quietly spoken police officer of the German or Austrian type?

Austrian!

[mikeloadsasaabs]

I feel sure that trying the stick on pads would be worth while.  See here http://www.ebay.co.uk/itm/Brake-Pad-Anti-Squeal-backing-pads-3M-x4-ASK1-/191314514764

Ordered this morning Mark.

Another thought is that when I replaced the pads, I just put copaslip on the back of the pads without cleaning the actual caliper. I'll try a thorough clean and degrease of that to get rid of any existing dust that's amalgamated with the grease. Ideal job for the cold winter 

[Mark B]

Mike,

ideally you should clean and wire brush the edges of the pads and the slides of the bracket that the pads sit in, and then apply copaslip only to these areas to ensure that the pads can move easily.  Clean the back of the pads and the piston face and the other side of the caliper that contacts the outer pad.  Apply the sticky pads to the back of the brake pads to cover the area where the piston and the outer part of the caliper hits the pads.  The idea is that there is no direct contact between the pads and the piston or outer caliper, so that there is a slight damping effect.  This may mean that you have to cut the stick on pads to fit where the piston touches the inner pad.

Mark

[pompey]

I'll be swapping back to my normal, non-winter tyres and wheels shortly and will be checking the brake pads and disks in the process as I suspect that, following my discovery of Bosch spark plugs in my 2.3T engine from the last service, they might be patent parts as opposed to genuine Saab parts. I have some spare EBC Red Stuff pads for the front that I'll use if that is the case but I have a quick question...

Is it OK to do what I thought was the usual trick and loosen/take off the brake fluid cap for when I push the pistons back into the calipers or, as the Haynes manual suggests, could this damage the system?

[sgould]

I've seen Haynes say this, but i've have always just pushed the pads back and siphoned off any fluid before it overflows. It shouldn't go that high, but if a garage has topped it all up...

[mikeloadsasaabs]

Is it OK to do what I thought was the usual trick and loosen/take off the brake fluid cap for when I push the pistons back into the calipers or, as the Haynes manual suggests, could this damage the system?

I always used to do this, but read in a couple of places that this could lead to damage. I've taken to loosening the bleed screws on the relevant caliper and letting the fluid out there the last few times. Can't say whether it's made any difference! 

[mikeloadsasaabs]

Mike,

ideally you should clean and wire brush the edges of the pads and the slides of the bracket that the pads sit in, and then apply copaslip only to these areas to ensure that the pads can move easily.  Clean the back of the pads and the piston face and the other side of the caliper that contacts the outer pad.  Apply the sticky pads to the back of the brake pads to cover the area where the piston and the outer part of the caliper hits the pads.  The idea is that there is no direct contact between the pads and the piston or outer caliper, so that there is a slight damping effect.  This may mean that you have to cut the stick on pads to fit where the piston touches the inner pad.

Mark

....will be tackling this job on or around April 15th, when the winter wheels come off and the summers go on. I'll see whether I put the shims on, I might just try cleaning everything up properly and see how it goes. Plus the joys of changing the auto trans fluid 

[pompey]

I always like to have a go at doing the more straightforward jobs myself but I always worry when it comes to the brakes. If I loosen the bleed nipples to let out the excess fluid when I push the caliper back is there any danger I will get air into the system?