Mintex Front Discs & Pads

[james250]

So i replaced my front discs and pads on my IS250 with mintex versions mainly because of the price. Ran well for a while but now i've started to notice alot of judder/vibration when gently applying the brake at high speeds, if i apply brakes harshly at high speeds then it's fine but gentle braking at high speeds causes this vibration.

I'm assuming the problem is with the discs and not the pads as i've used mintex pads in the past but not the discs. Considering removing them and putting OEM ones on. Also the mintext discs dont have the hub section painted black like the OEM does and as a result it's become rusty and looks horrible.

anyone had experience with mintex?

[ChrisIS200SportTTE]

I would say something else maybe causing your judder not just the fact the brakes are Mintex. Mintex are a very good brand and I've used them a lot in the past, never any problems.

Maybe a calliper is sticking?

[james250]

I would say something else maybe causing your judder not just the fact the brakes are Mintex. Mintex are a very good brand and I've used them a lot in the past, never any problems.

Maybe a calliper is sticking?

Any particular way to quickly check if caliper is sticking?

[ChrisIS200SportTTE]

jack the car up. Wheels should spin freely :)

[james250]

Jack the car up. Wheels should spin freely :)

Thanks, do you know what would be good for lubricating the bushings of the sliding bolts? I've seen some people use regular brake copper grease

[Mouser]

Juddering really shouldn't happen, and is a fairly serious matter. The disks may need to be turned flat on a lathe if they're in poor condition, but it's fairly unusual. Do you get any wobble/vibration at speed which could be caused by wheels being out of balance?

[Carl911]

Jack the car up. Wheels should spin freely :)

Thanks, do you know what would be good for lubricating the bushings of the sliding bolts? I've seen some people use regular brake copper grease

The sliders attend to rust up and retain build up of Brake dust over the years. I attend to clean them off using a flat screw driver to remove the worst of the loose debri then you could use a bit of sand paper to remove any rough edges. Possibly a small dremal bit would work. Finally, a small amount of copper grease applied to the slider. Not too much as you don't want grease getting on your brake pads. You could check that the caliper pistons are working correctly by using a G- clamp to carefully and slowly wind them in. Make sure the Brake fluid reservoir cap is loose with a bit of rag to catch any over flow. Then screw reservoir cap back on and slowly depress the brake pedal to pump out the calliper, you only need to bring the piston out 10mm to check its working. Too far might pop the seals.

If ll looks to be working ok, then repeat procedure by winding piston back in and refitting brake pads. Don't forget to fit the shims or else your have squeals. I think there are two shims per brake pad.

Given how dangerous it would be to mess around with your brakes I'd say only carry out any work in this area if you truly feel confident to do it properly, otherwise take it to a garage.

Carl

[steve2006]

Jack the car up. Wheels should spin freely :)

Thanks, do you know what would be good for lubricating the bushings of the sliding bolts? I've seen some people use regular brake copper grease

I found that the copper grease dries out very quickly so now use the dark cloured moly sulphide stuff, there is apparently special grease available for them.

[james250]

Do you get any wobble/vibration at speed which could be caused by wheels being out of balance?

Nope no wobble or vibrations of any kind unless i lightly brake from high speeds. If i brake hard then no vibrations or judder.

Carl911, thanks for the detailed info. Will give my brakes a thorough check this weekend. I'm suspecting maybe the sliding pins as I dont remember lubricating them. I'm guessing i can remove the brakes pads and check the sliding pins are allowing the caliper to slide back and forth freely. I'll lube the sliding pins with CARLUBE SILICONE GREASE. Can i use copper grease around the edge of brake piston? or should i use the same Silicone grease?

So to summarise, i'll check the piston is retracting with a clamp, lube sliding pins and check if caliper freely moves back and forth. anything else?

Thanks

[james250]

OK i've found the source of my brake judder and vibration, the front drivers side caliper mounting bracket that has the bushings that allows the caliper to move back and forth has one of the sliding pins seized, the top one doesnt move at all and has seized up. So it seems that I need a complete new bracket as this sliding pin seems to be integrated into the bracket. Anyone know how much this costs or have a part number for it?

[ColinBarber]

you should be able to get the pin out, clean it up and reuse it. I've had a few that have been seized but a bit of penetrating oil, time and some mole grips and it will come out. Just be careful not to damage the rubber boot, otherwise you will feel aggrieved having to spend £10+ on a piece of rubber that costs 20p to manufacture.

[james250]

you should be able to get the pin out, clean it up and reuse it. I've had a few that have been seized but a bit of penetrating oil, time and some mole grips and it will come out. Just be careful not to damage the rubber boot, otherwise you will feel aggrieved having to spend £10+ on a piece of rubber that costs 20p to manufacture.

Any suggestions on how i can achieve this? there seems to be a nut like thing which i am assuming is the pin going straight through the bushings. this nut like thing can be rotated but the pin just simply doesnt go back and forth like the one at the bottom, its completely stuck from going back and forth. how do i even go about removing it? i was looking at the costings and it seems that all these components do come apart just not sure how i would take that pin out.

Many thanks

[james250]

OK so i managed to free up the sliding pin, but unfortunately the rubber boot has a crack in it so had to order one. In the meantime, i cleaned the sliding pin thoroughly and lubricated it and put it back in and out few times. its now moving nicely however because the rubber boot is cracked, some of the lubricant leaks out so i doubt it will stay lubricated for too long, need to replace the boot asap. Once i get the replacement rubber boot, how do i replace it? the end that goes onto the slider pin is straight forward as it just slots in, but the end that goes into the caliper carrier seems to be stuck as if it is glued on or something? also, the seized caliper pin has a rubber ring on it which has damaged so i've ordered a replacement of that too.

Also, i noticed that when tightening the bolts that hold the caliper to the sliding pins, the inner nut of the sliding pin just rotates and doesnt allow me to tighten the outer screw, so i held the inner slider nut with a spanner and tightened the outer one to 34nm.

many thanks for your help.