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i have a problem with my front brakes. Both sides... (355mm str facelift brakes, or xf 5.0 na)
my inner pads (piston sides) do not sit parallel with the rotors. They sit with their lower edge (the one by the hub) towards the rotor and the upper edge is tucked in in such way that they do not touch the rotors on its outter edge, not even on braking.
Piston seems parallel and straight See how the disk is polished by its center? See how the outter edge of the pad doesn't get contact (upper view) See the same thing (exterior view)
I took pictures today.
everything is cleaned, piston seems straight
pads and rotors are surfaced perfectly.
both calipers do the same thing
old pads had diagonal wear... si clearly something is off
I can think of five possible reasons for this:
1. You’re looking at this when the wheel is off and the disc has no securing screws installed, causing it to move at an angle.
2. Incorrectly installed springs in the calliper hangars or rust behind them pushing them out of line.
3. Poorly manufactured pads.
4. Poorly manufactured discs.
5. One of the sliding pistons is seized (assuming your brakes are of the sliding piston type and not opposing pistons).
Last edited by Sportston; Oct 30, 2022 at 03:46 PM.
I can think of five possible reasons for this:
1. You’re looking at this when the wheel is off and the disc has no securing screws installed, causing it to move at an angle.
2. Incorrectly installed springs in the calliper hangars or rust behind them pushing them out of line.
3. Poorly manufactured pads.
4. Poorly manufactured discs.
5. One of the sliding pistons is seized (assuming your brakes are of the sliding piston type and not opposing pistons).
awesome points.
i personally was convinced it was the rotor that's not tight, but then i remembered i have spacers installed so they keep the disk tight, haha.
caliper springs and pistons are perfect, i used a digital measuring caliper to check all the distances and they are good.
Pads and disks were new but they sat a long time on standby, so i had them resurfaced and measured with a caliper and they are perfectly flat.
i must send ate an email.
maybe my textar pads are just stupid. I mean they dont even cover the whole disk area. But their part number matches these calipers and they fit right in the slots.
i am wondering if the calipers have settings in regards to the pads-rotors gaps
I’ve never heard of Textar. I wonder if that is the problem.
I would suggest trying a quality brand. EBC are, in my experience, the best value for money (you don’t need to opt for the gimmicky sintered green stuff or red stuff. Their standard ones are best). Mintex are ok. Lucas TRW are ok. Blueprint are ok. Delphi are another good one as are Bosch.
AVOID Ferodo! They are poor quality these days.
When buying brake components, always go for quality stuff. It is a false economy to buy the cheapest discs and pads because they either warp, squeal, or don’t fit or work well. Also make sure they are the right part listed for your car.
One other thing to check: some pads have a raised locating blob on the back. These are designed to fit on the opposite side to the piston. The ones on the piston side have no blob. If you have installed them the wrong side the blob can cause uneven pressure.
Did you check both the sliding pistons move freely?
Last edited by Sportston; Oct 30, 2022 at 08:05 PM.
Yep, I wouldn't worry about Textar quality, it is the top brand from TMD in Europe above Pagid and the budget Mintex, and an OEM for many car manufacturers. Ferodo is part of Federal-Mogul and they are producing some very good high-friction road pads these days, along with their sister brand Jurid. I have the Jaguar/Jurid 233 pads up front and Ferodos on the rears. Best road combination for the Lucas brakes on the older S-Types I have yet come across.
However, for the later S-Types with the ATE brakes, they are single piston types, right? I would make sure that every moving part moves freely, including the piston itself. A sticky piston could well cause the problems you describe, allowing the pad to drag more than it should.
Yep, I wouldn't worry about Textar quality, it is the top brand from TMD in Europe above Pagid and the budget Mintex, and an OEM for many car manufacturers. Ferodo is part of Federal-Mogul and they are producing some very good high-friction road pads these days, along with their sister brand Jurid. I have the Jaguar/Jurid 233 pads up front and Ferodos on the rears. Best road combination for the Lucas brakes on the older S-Types I have yet come across.
However, for the later S-Types with the ATE brakes, they are single piston types, right? I would make sure that every moving part moves freely, including the piston itself. A sticky piston could well cause the problems you describe, allowing the pad to drag more than it should.
I take it you haven’t noticed the Ferodo tendency to squeal then? I stopped using them due to customer complaints about noise. Mind you, that was 7 yrs ago. I guess they could have improved since then.
I take it you haven’t noticed the Ferodo tendency to squeal then? I stopped using them due to customer complaints about noise. Mind you, that was 7 yrs ago. I guess they could have improved since then.
Nope thankfully But I only have experienced light squealing when the calipers are clogged up and so probably pretty much independent of pad manufacturer. The XKR has just come through it's bi-annual TÜV test and the GG rated Ferodos put up results that are the best yet and they somehow really minimize that light graunching noise that automatics always seem to make from the front brakes on a very light stop. On the move they are absolutely fine. The S-Type also has no problems except for the naturally rather heavy pedal. Here, high friction pads all round really help to give a bit more bite at light pressures. At heavier pressures it always seems to work fine.
The 2006+ STR brakes are different than the Bremo's of the previous models, they are ATE-Teves and most part sellers tend to give you the wrong parts. I have replaced the front brake discs and brake pads and after some research I found the correct ones but the part seller would not give me a free return guarantee because he was certain that this where the wrong parts. But they fit.
I'am not sure of this remark i intended for me, but if I have done something wrong it was not my intention to do so. I was replying only ones to a post of alDariusVargas regarding his brakes.
I'am not sure of this remark i intended for me, but if I have done something wrong it was not my intention to do so. I was replying only ones to a post of alDariusVargas regarding his brakes.
It wasn't about you - the person concerned looks to have been banned & posts removed.
Before i installed these XF 5.0 or STR calipers on my stype, theyve been rebuilt and greased with ate caliper grease, everything like new.
Still dont know why the angle was weird regarding the inner pads, but i drove it like that afterwards.
of course they worn out 1mm and now they sit right on the disk, but still, if i were to put new pads and disks, chances are thy gonna sit angled in the beginning.
Now as an experience after the upgrade: low speeds you can feel slightly more braking power, but above 50kmh, i have leverage with these wide disks. Way easier to stop the car. i mean, from 280mm (iirc) to 355mm, it is noticeable difference!
As you guys described the s type's hard pedal, its weird, and i might also try to add a vaccum canister to test if i can increase the braking power.
i am wondering if these brake boosters are notorious for any faults? is there something special to test them for? If i shut down th engine with the brake pedal pressed it doesnt push me back.
Thanks
Not sure what you mean by a vacuum canister?
Your power brakes are vacuum powered already?
.
.
.
it stores vacuum. mostly used in applications where the engine cant produce enough. cammed engines, old big block engines etc
thats regarding s type hard brake pedal. lets see what happens.
Last edited by elDariusVargas; Dec 28, 2022 at 05:10 AM.
Str 2006+ 355mm brakes
But I only have experienced light squealing when the calipers are clogged up and so probably pretty much independent of pad manufacturer. The XKR has just come through it's bi-annual TÜV test and the GG rated Ferodos put up results that are the best yet and they somehow really minimize that light graunching noise that automatics always seem to make from the front brakes on a very light stop. On the move they are absolutely fine. The S-Type also has no problems except for the naturally rather heavy pedal. Here, high friction pads all round really help to give a bit more bite at light pressures. At heavier pressures it always seems to work fine.
