# Switching Rear Aluminum Calipers to Cast Iron?



## Crimson_King (Mar 12, 2011)

I have a '02 Jetta GLS with 120k. A mechanic has advised that the rear aluminum calipers need to be replaced and he only he only uses cast iron calipers as a replacement. The original rear brakes and calipers lasted 75K. Has anyone switched rear calipers?


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## greyhare (Dec 24, 2003)

Ask him why. 

There is no good reason to go with the older calipers. The steel calipers are heavier and as far as I can tell, more prone to binding.


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## Little Golf Mklll (Nov 27, 2007)

Did he say why they need to be replaced? (seized or leaking seal) And as Greyhare said The aluminum calipers are actually upgrades to the cast iron of the mk3 generation.


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## Crimson_King (Mar 12, 2011)

The reason why this mechanic only uses cast iron calipers because the aluminum ones do not last because they corrode. I live in Chicago so my car is abused by the weather and road salt. His thought is to save the customer money in the long run and install longer lasting parts. The original rear calipers were already replaced so this would be my third set. I have had three independent mechanics tell me aluminum calipers don't last on any car but VW is insisting that they rarely change calipers.


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## GTijoejoe (Oct 6, 2001)

Crimson_King said:


> The reason why this mechanic only uses cast iron calipers because the aluminum ones do not last because they corrode. I live in Chicago so my car is abused by the weather and road salt. His thought is to save the customer money in the long run and install longer lasting parts. The original rear calipers were already replaced so this would be my third set. I have had three independent mechanics tell me aluminum calipers don't last on any car but VW is insisting that they rarely change calipers.


 :screwy::screwy::screwy: 

I apologize but I have no faith in your mechanic's advice... aluminum calipers have a couple benefits to the fact that they are lighter and they have superior corrosion resistance than iron, the dwg backs are they are more expensive and requrie more material to equal the stiffness of iron. 
Iron calipers need special coatings to keep them from corroding... thats why they look grey/siliver 

Now that being said, aluminum also has glavanic corrosion, so if the slide pins are not properly treated to act against it, the steel slide pins will eat the aluminum caliper....but I'm sure that is highly unlikely coming from vw not to guarantee that, all caliper suppliers understand this. 

If you actually saw corrosion results from and iron vs. Al caliper in a corrosion chamber (w/ salt spray), you'll see that your mechanic friends are not educated enough on the subject and gave you poor advice :thumbup: 

If you still doubt me, there are aluminum calipers on MANY vehicles which are non painted, unlike many painted fixed piston calipers (since the 90's). The most important part of a sliding caliper to fight against corrosion is the caliper brkt, because the brkt serves as the sliding surface for the pads, corrosion builds up on the brkt and binds the pads....this corrision should be cleaned off during brake jobs (not many ppl actually know that), behind the pad retainers. I'm pretty certain that in your case your caliper is probably only an Aluminum body, and the brkt is still iron so any corrosion concern would be same as a entire iron caliper anyways (correct me if I'm wrong) 

I'm curious to understand what you mechanic is actually experiencing to make such judgments.


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