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2006 smarty

brake rotor contacting brake caliper bracket

24 posts in this topic

Dear Forum Members:

I was swapping my winter tires to my summer tires when I noticed the front brake rotor contacting/rubbing against the brake caliper bracket. See my youtube video here: https://www.youtube.com/watch?v=nPX7TJJZLu0

I replaced my pads and rotors 2 years ago; these parts have approximately 11,000km on them. Also, the inner side of the rotor and inner brake pads were rusty as if no contact was made between them.

I removed the pads, rotors, and the hub/bearing assembly; I couldn’t feel any movement in the hub/bearing assembly before taking the wheels off the vehicle.

The instructions on the OE smart fortwo brake rotors state “if the clearance between brake disc and brake caliper bracket is undersized respectively if the brake disc touches the brake caliper bracket, the brake caliper bracket and/or the knuckle or wheel bearing must be renewed.”

Prices for the parts from the dealer are: knuckle: didn’t ask; wheel bearing: $178/each; brake caliper bracket: $240/each.

I did have an alignment done at the dealer 3 years ago everything checked out okay, with the exception of right front camber, it was out of range, before: -0°31, after: -0°23 (don’t know what this means).

Before I start throwing parts at my vehicle, could I have your opinions? (My guess is to replace the hub/bearing assemblies and hope it solves the problem??)

thank you,

2006 smarty.

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If you have to buy parts and can wait to get them from a vendor in Europe go that way. Parts may be half the cost of dealer pricing.

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Build up of rust on caliper carrier. You have to knock that off. There may also be build up of rust on the outer diameter of rotor. Knock that off too.

The easy way to remove the rust is by electrolysis. See my thread on Smartmaniacs for further details.

http://smartmaniacs.co.uk/forum/the-cars/fortwo-450-sept-1998-oct-2007/872178-rust-removal-will-there-be-anything-left

I treated my subframe and rear axle but I can assure you that it works a treat with anything rusty. Rusty old rotors becomes like brand new.

PS. I am removing rust off my exhaust manifold and turbine housing at the moment.

Edited by tolsen

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thank you Huronlad and Tolsen, @ Huronlad: thanks for the advice, being impatient I bit the bullet and ordered everything from the local dealer, hub/bearing unit $172, each, rotors (pair) $137, pads $68, backing plate in behind hub/bearing $30 each, hub/bearing cap cover $4.81 each, total with tax $650. (some other prices I inquired about: caliper rebuild kit $147 each side. @ Tolsen: wow, that electrolysis is very impressive! Thank you for telling me to knock off the rust, I grabbed my grinder and sand paper and removed as much rust as possible, both from the carrier and rotor.

One other question: After lubeing the caliper guide pins I noticed the bottom slider was still very stiff, I noticed there is a rubber o-ring on it, I suspect it has swollen, can I remove it? (you cannot purchase sliders separetely, they only come with the caliper bracket).

thanks,

2006 smarty

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I was swapping my winter tires to my summer tires when I noticed the front brake rotor contacting/rubbing against the brake caliper bracket.

When you previously did the brake job , did you loosen the lower caliper bolt? It's a special 5 sided that bolt and holds the rotor in correct alignment.

It should be left alone. I notice on some cars that I service that the lower bolt is now on top.

To date I have not seen the rotors contact the brake caliper bracket.

I have yet to see a caliper failure.

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I just noticed Rockauto has hub bearings, $40 each. The dealer will always be the most expensive place to buy parts. Pads and rotors can be bought for 1/2 the price you paid.

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Rubber ring on lower caliper slide pin will swell if you use mineral based grease. Both pins need a clean and relube from time to time. Through away the pentagonal bolt and fit a standard one. The 451 has standard bolts on both pins.

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fyi - a local rebuilder has rebuilt calipers for $100.

I supplied them with some from my parts cars and they rebuilt them.

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Slide pins are available after market. There are also caliper rebuild kits containing hydraulic seal, dust seal, slide pin dust seals, lower slide pin rubber ring, hydraulic grease and slide pin grease.

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Calipers are easily rebuilt. Check out the transformation of mine:

MyRustyCalipers.jpg

NoMoreRustyCalipers.jpg

DSC04055.jpg

Rebuilt wheel cylinders too:

87658c45-c836-46da-a802-2cfabb64ceb4.jpg

All coated in two pack epoxy for a long lasting protection from the elements.

Cleaned also up and painted caliper carriers and exposed parts of slide pins but have no photo. Made new splash guards out of plastic camping plates:

DSC03962.jpg

Fitting bolts for steering ball joint as shown did not work. Nuts were touching rotor.

DSC03964.jpg

Edited by tolsen

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Just wondering if the OP has established the actual cause for rotor contacting brake caliper carrier. Where exactly is the contact point? Both sides or limited to just one caliper?

Edited by tolsen

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I would think that if he hit something and bent it out of whack, that there would be a rather nasty dent in his rim.

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@ smart142: yes I did loosen the lower caliper bolt, I replaced the 5 sided penta bolt with a hex bolt, below is my previous video on how I removed the pads, rotors including the lower 5 sided guide pin bolt:

@ Huronlad: thank you for the info! Rockauto is my new friend! Their prices are very reasonable and I am surprised they carry so many parts for the 450.

@ tolsen: I used Permatex Ultra Slick synthetic brake lubricant, the package says that it is safe on rubber components, will not swell them etc. Your finish on the calipers, carriers, knuckle is awing. I love the idea of the plastic camping plates for the splash guards!

@ tolsen & marchanna: I am the second owner of the vehicle and have the full dealer service history, there was one note when the owner asked to check the right front wheel for damage and dealer wrote no fault found, I had an alignment done and noted the specs in my previous post above, I also do not see any visual bent damage; the rotor contacting the brake caliper carrier was on the left side (driver’s side), inner top part of the rotor.

I think I may have found the possible culprit, I noticed that both lower guide pin (sliders) were very hard to move, I replaced on both sides the lower guide pin o-ring (the rubber gear looking o-ring – this is what they look like: http://www.stockwiseauto.com/product_info.php/cPath/1106_1227/products_id/1816128/Make/Smart/Model/Fortwo)

and now both the lower sliders are much easier to move, I also compared the old and new o-rings and the old ones looked quite swollen, so I now I am really suspecting those lower sliders.

I called the dealer today and all my parts are in so I will be putting everything back together and will report back on progress, I will also upload a video.

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@ smart142: yes I did loosen the lower caliper bolt, I replaced the 5 sided penta bolt with a hex bolt,

There is NO need to remove the penta bolt on the bottom. It holds the rotor and caliper in correct alignment. That's why your rotor was contacting the caliper bracket.

They made it a 5 sided penta bolt, and difficult to remove, because they didn't want you to remove it!!! It was aligned at the factory.

I pity the poor folks that will follow your guide on You tube and buy, and then remove, that bolt with the special tool from Sears. A very good chance they will have the rotors rub against the brackets.

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I would think that if you painting your callipers and brackets you would probably want to remove that bolt.

Just for curiosity sake, does it have axial or lateral adjustability? Ie, an elongated through hole? I'm not sure how this bolt provides alignment.

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It is clearly stated in the heading and at the start of this thread that rotor was touching caliper carrier, not caliper. Could the OP kindly provide further clarification on this issue?

Another poster has twice warned against touching the pentagonal bolt on lower caliper pin. I strongly recommend cleaning both caliper pins from time to time and at least confirm they move freely whenever brakes are being serviced. As the car ages, caliper pins gets rusty allowing water ingress. The pathway is via the grove on the pin where the small rubber gaiter is supposed to seal. The rust cakes up allowing water to pass through. Below you can see condition of two of my caliper slide pins about five years ago.after 8 years of service. The pins have been cleaned up. One can clearly see pitting on lower pin and in the grooves where gaiter should seal. Less pitting on top pin since that one had been subject to more frequent servicing.

DSC02204.jpg

Purpose of the axially grooved rubber ring is to limit noise and vibration. Brakes will work perfectly without this ring but there may be some noise.

Keep copper slip and mineral based grease of any kind well away from your brakes as these will ruin the rubber seals. I use Castrol red rubber grease for hydraulic parts of brake calipers and wheel cylinders and use silicon based grease for the slide pins. I have in the past used copper slip to lube contact points between pads and caliper carrier but have found it does not stay on for long. Silicon based grease stays on for longer.

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Graphite spray also works as an excellent lubricant. It's a dry lubricant and therefore less risk of contaminating the rotor or pads.

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That is correct, there was contact made between the inner rotor and caliper bracket/carrier (not caliper) on the drivers' side; contact was made at inner, most upper side of rotor and caliper bracket/carrier.

I replaced all parts yesterday evening and even though there is no contact between rotor and caliper bracket, the clearance between them respectively is just under 0.5mm (inner side) -- I could not get a 0.58mm feeler guage between inner caliper bracket and rotor, the outside distance between rotor and caliper bracket is very good, no issues their. I am afraid that in a short time the problem will resurface (sorry no video as I was tired at the end of the evening). On a brighter note, I believe the almost seized lower caliper guide pin problem has been rectified, time will tell if this is so.

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It sounds to me as though the carrier has been bent.

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Have read through the whole thread again. Shimming caliper carrier as I suggested in previous post will only make things worse as this will bring carrier further outboard nearer rotor.

Possible causes:

Rotor is aftermarket and its dimensions not within tolerance.

Bent steering knuckle.

Steering knuckle is out of tolerance.

Start fault finding by swapping rotors.

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widen that caliper bracket gap with a grinder or hand file until only fresh metal shows (and install fresh rotors which youve already done)

i run into same problem on many gm brake jobs..rust builds up on bracket and on rotor edges

edited to add: also clean the boss area where the mounting bolts go ...both on knuckle and caliper bracket...it just takes a small bit of dirt or rust there to make clearances out of whack

Edited by LooseLugNuts
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thank you LooseLugNuts and Tolsen, removed the caliper carriers and thoroughly cleaned them with a wire brush, problem solved;

that rust can sure be a real bugger!

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