# Will brake fluid corrode aluminum **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [December 8, 2013, 8:48pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585 "2013-12-08T20:48:53Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![JuniorMint](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JuniorMint](https://community.cartalk.com/u/JuniorMint)\ **Post date:** [December 8, 2013, 8:48pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/1 "2013-12-08T20:48:53Z")
Will brake fluid corrode aluminum? There’s pitting on my trailing arms and dust shields, in a peculiar spray pattern. UPDATE: now that we are done with this trivial question, here’s a pic of the pattern I am talking about. I think it is from water condensation and then the water droplets drying out. It really does seem like pitting… but perhaps not - won’t know for sure until the day I brush it clean… ---
**Author:** ![SteveF](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/stevef/32/2_2.png) [@SteveF](https://community.cartalk.com/u/SteveF)\ **Post date:** [December 8, 2013, 9:16pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/2 "2013-12-08T21:16:58Z")
Brake fluid is essentially non-corrosive. It will not react with aluminum, nor much of anything else. Some car owners replace their brake fluid at regular intervals but this is because the fluid can absorb moisture which does have corrosive properties. If you see pitting on the trailing arms and dust shields, brake fluid is not the culprit. ---
**Author:** ![knfenimore](https://avatars.discourse-cdn.com/v4/letter/k/9fc348/32.png) [@knfenimore](https://community.cartalk.com/u/knfenimore)\ **Post date:** [December 8, 2013, 11:19pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/3 "2013-12-08T23:19:22Z")
Brake fluid will strip paint quickly. ---
**Author:** ![art1966](https://avatars.discourse-cdn.com/v4/letter/a/77aa72/32.png) [@art1966](https://community.cartalk.com/u/art1966)\ **Post date:** [December 8, 2013, 11:34pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/4 "2013-12-08T23:34:05Z")
Are the trailing arms and dust shields really aluminum? ---
**Author:** ![JuniorMint](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JuniorMint](https://community.cartalk.com/u/JuniorMint)\ **Post date:** [December 9, 2013, 12:50am UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/5 "2013-12-09T00:50:33Z")
@art1966 yes and probably - come to think of it, the only such corrosion (appears as white specks) is on the rear shields, not the front, and the front I think is painted or something. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [December 9, 2013, 1:10am UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/6 "2013-12-09T01:10:12Z")
@SteveF Sorry, but I gotta disagree with you on this I know from professional experience that brake fluid will very quickly cause paint to blister and flake off I’ll give a really good example . . . if you encounter a vehicle with a brake master that was leaking externally, take a good luck at the booster. More likely than not, the booster will have flaking paint right below the master cylinder I realize that brake boosters don’t have an aluminum shell. They are stamped steel and are painted. In any case, spilled/leaking brake fluid should be hosed off with water as soon as possible. And the cause of the leak should immediately be repaired. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [December 9, 2013, 1:15am UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/7 "2013-12-09T01:15:16Z")
No. Most brake and clutch master cylinders are cast from an aluminum alloy. Tester ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [December 9, 2013, 2:12am UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/8 "2013-12-09T02:12:52Z")
@Tester I’m not talking about the master cylinder . . . I know they’re made from aluminum I’m talking about the brake booster and the car’s paint They are not made from aluminum and the brake fluid will most certainly damage them (the paint, at least) ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [December 9, 2013, 3:47am UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/9 "2013-12-09T03:47:11Z")
@db4690 JuniorMint asked if brake fluid can corrode aluminum. And the answer is no. Tester ---
**Author:** ![JuniorMint](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JuniorMint](https://community.cartalk.com/u/JuniorMint)\ **Post date:** [December 9, 2013, 4:13am UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/10 "2013-12-09T04:13:15Z")
@Tester good point - I had forgotten, the BMC is made from aluminum! “JuniorMint asked if brake fluid can corrode aluminum. And the answer is no.” perfect ---
**Author:** ![JuniorMint](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JuniorMint](https://community.cartalk.com/u/JuniorMint)\ **Post date:** [December 13, 2013, 7:26pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/11 "2013-12-13T19:26:58Z")
Bumping this up (?) because I finally added a pic of the area in question, incase it helps at all. ---
**Author:** ![PvtPublic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/pvtpublic/32/13089_2.png) [@PvtPublic](https://community.cartalk.com/u/PvtPublic)\ **Post date:** [December 13, 2013, 8:10pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/12 "2013-12-13T20:10:10Z")
I don’t think anything in the picture is aluminum. ---
**Author:** ![dagosa](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/dagosa/32/9837_2.png) [@dagosa](https://community.cartalk.com/u/dagosa)\ **Post date:** [December 13, 2013, 8:26pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/13 "2013-12-13T20:26:41Z")
Brake fluid itself will not corrode metals, but if the corrosion inhibitors in the fluid break down over time, corrosion could occur. There is the potential for moisture to be present. Aluminum is not automatically immune to corrosion. I have seen aluminum exhibit significant corrosion in many marine situations. But, fresh brake fluid is not going to cause it. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [December 13, 2013, 9:25pm UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/14 "2013-12-13T21:25:03Z")
“There’s pitting on my trailing arms and dust shields, in a peculiar spray pattern.” You can see if the shield is aluminum with a magnet. The white speckles look like salt deposits to me. ---
**Author:** ![JuniorMint](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JuniorMint](https://community.cartalk.com/u/JuniorMint)\ **Post date:** [December 30, 2013, 2:43am UTC](https://community.cartalk.com/t/will-brake-fluid-corrode-aluminum/82585/15 "2013-12-30T02:43:55Z")
I finally got back to this. the shield shown is not magnetic @PvtPublic @circuitsmith. however, the front set is. go figure. also the front shields are badly corroded, but the rears cleaned up OK. I wire brushed them real good - still some pits, but I think what happened - like someone said, sorry didn’t cite - some liquid dissolved the brake dust but did not affect the aluminum. The liquid was either water (likely from sitting around with horrendous condensation), or brake fluid spatter. thanks for the help anyways -even though the answer was in prior to all the other discussion.