ECS Performance Caliper Guide Bushings

[fR3ZNO]

Picked up a set of the ECS caliper guide bushings. I'm having an issue with the o-rings that are supplied with the kit. They are meant to keep out dirt and dust from the slider pins, so I'd like to utilize them.

The issue is that the ID of the supplied o-rings is too small, thus making it nearly impossible to install the slide pin into the bushing. As a test, I gently pressed the pin into the bushing use the vise on my bench. As it pushed through, it cut a thin ring of material from the o-ring. After the o ring was cut, there was still a lot of drag on the pin (even with lube, ( ͡° ͜ʖ ͡°)).

I checked my collection of o-rings and don't have anything with the same OD and larger ID.

Without the o-ring, there's no issues and the pin slides easily in the bore.

I'd like to know if anyone else had a similar issue installing these.

Click for install PDF for pics

[fR3ZNO]

Update, matched the supplied o-ring with one of the o-rings in my assortment from HF. Looks like the dimensions are:

OD: 16.6mm
ID: 11.8mm
section/width: 2.4mm

Measured the slide pins and bushing as well:

Pin OD: 11.95mm
Bushing ID: 12.01mm

(12.01-11.95)/2 =

Therefore, roughly 0.03mm of clearance... Assuming no squeeze on the o-ring, (bushing ID - ID)/2 = (12.01-11.8)/2 = 0.105mm of o-ring is sticking out past the bore of the bushing...

This would explain why the pin will not fit without cutting the o-ring... ugh



PS sorry not sorry for doing math on a Sunday

[5ktq]

That doesn't sound crazy, you do want the oring to interfere or it won't seal...

[fR3ZNO]

That doesn't sound crazy, you do want the oring to interfere or it won't seal...

Yeah, but not to the point that the slide pin won't slide into the bushing...

[fR3ZNO]

When not installed in the bushing, the o-ring slides on the pin with very little drag. I am thinking that the groove ID in the bushing is smaller than the OD of the o-ring, creating too much "squeeze". I've been looking on McMaster Carr and thinking about going with a 12mm ID, 2mm section width o-ring. That should help allow a smaller amount of "squeeze" on the o-ring.

In this application, there is no fluid pressure to contain and it's a dynamic seal since the slide pin needs to, well, slide. So, excessive amounts of squeeze are not necessary for sealing purposes.

I'll take a look at Lowe's or Home Depot first though, hopefully they have that size of o-ring in a quantity of less than 100 like McMaster...

[fR3ZNO]

Bump... Has anyone installed these bushings?

[diagnosticator]

You can order metric O rings online.

[fR3ZNO]

You can order metric O rings online.

I'm aware. I've been looking on McMaster Carr. Just have to measure the ID of the groove before I can determine what size I need.

I've contacted customer support, and they've never had a reported issue like mine before with this product.

[fR3ZNO]

Update. Got a bunch of o rings in different sizes.

The best size that I found after installing them into the bushings is 12mm ID and 2mm width. I went with a Viton o ring for the temperature range and chemical resistance. BunaN would be sufficient too.

With the new o ring, the pin slides into the bushing easily. No excessive resistance from the o ring. Lubricant is wiped away from the o ring as intended, therefore will seal out any dust and dirt.

I have a bunch of extras, if anyone is interested and has a similar issue. There was a minimum order number for each size required by the store I bought from.

Check out the pics:



You can see the width is slightly smaller.

[diagnosticator]

Where was the original O ring getting sliced, the OD or the ID?

How do you like the brakes with the stiffening kit installed, compared to before? Before you installed the kit, where the brake pads wearing evenly or not?

[fR3ZNO]

Where was the original O ring getting sliced, the OD or the ID?

How do you like the brakes with the stiffening kit installed, compared to before? Before you installed the kit, where the brake pads wearing evenly or not?

The original was getting sliced on ID.

That's a pic of the old o ring. You can see how far it sticks out.


I haven't installed the brakes yet. I'm in the process of rebuilding the stock calipers and going back to stock brakes.

[diagnosticator]

Request update after you install the larger calipers. You aren't going to stay with the stock calipers, right? There is no comparison between the larger B6 S4 and B7 A4/S4 front brakes and the original 1.8T/3.0 OEM front brakes.

[fR3ZNO]

Request update after you install the larger calipers. You aren't going to stay with the stock calipers, right? There is no comparison between the larger B6 S4 and B7 A4/S4 front brakes and the original 1.8T/3.0 OEM front brakes.

I am. After being unhappy with my B5 S4 front and B6 S4 rear in regards to pedal feel, I've decided to go back to stock calipers.

When I first got the car, I was happy with the pedal, so I figured that'd be the safest bet.

If my plans for the car ever change and require bigger brakes, I can just throw together a Touareg front caliper setup for like $600 shipped on RockAuto.

[Charles.waite]

I'm also interested in how you like the kit. I would assume since the bushing is press fit its snug in the carrier bore? I liked the performance of my Tyrolsport kit but was a bit perturbed at how loosely the bushing fit into the carrier bore. I actually thought they were introducing some rattle into the calipers going over bumps but that just turned out to be my pads. But after removing them to retest and installing them again, I ended up bending the snap ring (due to cheap, crappy snap ring pliers) and struggled to get them bent back straight enough to install them and still was a bit iffy as to whether or not they would securely hold in the bushing.

Anyway, I guess I've been eyeing up this ECS kit because I feel the press fit will be more secure and take out that last little bit of wobble...

[fR3ZNO]

I'm also interested in how you like the kit. I would assume since the bushing is press fit its snug in the carrier bore? I liked the performance of my Tyrolsport kit but was a bit perturbed at how loosely the bushing fit into the carrier bore. I actually thought they were introducing some rattle into the calipers going over bumps but that just turned out to be my pads. But after removing them to retest and installing them again, I ended up bending the snap ring (due to cheap, crappy snap ring pliers) and struggled to get them bent back straight enough to install them and still was a bit iffy as to whether or not they would securely hold in the bushing.

Anyway, I guess I've been eyeing up this ECS kit because I feel the press fit will be more secure and take out that last little bit of wobble...

I had the Tyrolsport kit on my B5 and had a similar issue. With the corrosion that occurs underneath the rubber bushings, it's difficult to remove the rust without removing the material required for the tolerances of a press fit. I had one bushing that ended up kinda loose in the caliper and left it.

So that was one thing that I liked about the ECS kit compared to the Tyrolsport kit. I also like the addition of the o rings to help reduce maintenance. On the Tyrolsport, it was recommended to regrease them every 5k miles or something which was a PITA. That's why I was so insistent on getting o rings that fit properly.

But apparently, ECS has no records of this being an issue before and probably think I'm crazy.

However, I screwed up the installation of the ECS bushing by using a die grinder to remove the rust and removed too much material. So I ended up using a coat of JB weld and now they are secure. The snap rings the ECS kit uses just act as a safety feature I suppose.

[fR3ZNO]

Small update. Installed the bushings the proper way in the other caliper.





Learned that it is critical to get these completely true. Otherwise, they will bind up on the slide pins once they are installed in the carrier.

I tried mounting the caliper that had JB weld to the carrier on the work bench. As soon as the slide pins were tightened, the caliper would bind on the slide pins.

I tried pressing the bushings in farther using my setup and they wouldn't budge. So, I would guess that the JB weld cured while the bushings were misaligned in the bores.

To get the bushings out, used a c clamp and heated up the outside. Softened the JB weld and came right out. So, it looks like I will have to get another caliper... ugh. Thankfully they're all off the car.

[ECS Tuning-Audi]

Sorry for the old bump, but I just wanted to chime in and mention that I have these installed on my B6. The stiffening kit is one of my favorite mods I have done. The pedal doesn't feel as spongy as it was in the past.

I too noticed that the o-ring was tight. Once I installed the carrier it was able to pull the pin through and left a small o-ring that was cut. I've had them installed for a couple months and haven't noticed any adverse effects. I'll follow up once I need to service them.

I also have an e-mail into our head engineer about the o-rings. I can report back once I have more info.

Jason

[fR3ZNO]

Sorry for the old bump, but I just wanted to chime in and mention that I have these installed on my B6. The stiffening kit is one of my favorite mods I have done. The pedal doesn't feel as spongy as it was in the past.

I too noticed that the o-ring was tight. Once I installed the carrier it was able to pull the pin through and left a small o-ring that was cut. I've had them installed for a couple months and haven't noticed any adverse effects. I'll follow up once I need to service them.

I also have an e-mail into our head engineer about the o-rings. I can report back once I have more info.

Jason

Thanks for the bump.

I'm glad I'm not the only with the o ring problem. I ended up just using an o ring with a larger ID.

I now have these calipers installed on my B6 and love the pedal feel. Much improved.

I also installed a set of these on a B5.5 Passat. I had a lot less issues this time around since I learned my lesson about removing too much material from the bore the bushing sits in.

Look forward to hearing what the head engineer has to say.

[ECS Tuning-Audi]

I removed just a bit too much rust from my calipers too. I ended up using a high temp sleeve/bearing retainer I applied to the bushings and then pressed them into the caliper. Let them cure for 24hrs and installed them back on the car.

Have been fine and havent budged since.

Jason

[fR3ZNO]

I removed just a bit too much rust from my calipers too. I ended up using a high temp sleeve/bearing retainer I applied to the bushings and then pressed them into the caliper. Let them cure for 24hrs and installed them back on the car.

Have been fine and havent budged since.

Jason

Yeah, I ended up doing something similar. Put some wicking thread locker in the gap.

I had also tried getting a remanufactured caliper, but that gap was even worse... makes sense since they bead blast the calipers to remove the rust.

[ECS Tuning-Audi]

Yeah, I ended up doing something similar. Put some wicking thread locker in the gap.

I had also tried getting a remanufactured caliper, but that gap was even worse... makes sense since they bead blast the calipers to remove the rust.

We did test them in a number of different calipers from new, used, to remanufactured across many different makes and models, which is why we chose to go with a splined press fit so they can work with various tolerances. This method works most of the time but it is clear that depending on caliper condition and cleaning process it is impossible to account for all caliper conditions that may exist. The snap ring will keep a loose fitting bushing functioning safely without working its way out of the caliper body.

We're still reviewing the o-ring spec, hopefully, I'll have some more information for you soon.

Jason

[fR3ZNO]

We did test them in a number of different calipers from new, used, to remanufactured across many different makes and models, which is why we chose to go with a splined press fit so they can work with various tolerances. This method works most of the time but it is clear that depending on caliper condition and cleaning process it is impossible to account for all caliper conditions that may exist. The snap ring will keep a loose fitting bushing functioning safely without working its way out of the caliper body.

We're still reviewing the o-ring spec, hopefully, I'll have some more information for you soon.

Jason

Oh, for sure. The splines were a good idea. Yeah, like you said can't account for every scenario.

[ECS Tuning-Audi]

It seems that when this project was transferred to the engineering team there was some inadequate documentation/communication during our original design revision. The proper o-ring is 12mmX2mm.

We have tagged our existing inventory to have the o-rings swapped out for the correct ones. If you have received our bushing kit customer service will send you the proper o-rings at no charge, you just need to call in.

1-800-924-5172 ex 134

We do apologize for this and are working diligently to make sure all customers are taken care of.

If you have any other questions please let us know.

Jason

[walky_talky20]

Good Stuff, Jason!

[fR3ZNO]

Thanks for acknowledging the issue and making it right. Interesting that you specified the same size o ring I used.

[fR3ZNO]

Just an update after getting the o ring sizes all sorted out, I've been enjoying the pedal feel with this upgrade. I also have ss braided lines and stop tech sport pads. Brake pedal has a very direct response and good feel and modulation. Perfect for a daily driver.