# Brake master cylinder seals for Chinese ev trike **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [May 17, 2026, 6:38pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699 "2026-05-17T18:38:00Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Josephc](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@Josephc](https://community.cartalk.com/u/Josephc)\ **Post date:** [May 17, 2026, 6:38pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699/1 "2026-05-17T18:38:00Z")
I have a 07 zap xebra truck. The seal at the rear of the master cylinder has given up and leaks fluid into the cab floor. I removed the maser cylinder and have disassembled. Problem is the there are no parts available for these guys. I’ve measured the rear seal and it is 20mm OD and 13mm ID. It has u shape profile. Where can I find such a seal? Is there a place to cross reference the dimensions of such parts? Thanks ---
**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:** [May 17, 2026, 6:43pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699/2 "2026-05-17T18:43:02Z")
This is my go-to supplier for unique parts/components. > **[McMaster-Carr](https://www.mcmaster.com/products/hydraulic-seals/)** > > McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day. Tester ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [May 17, 2026, 6:48pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699/3 "2026-05-17T18:48:24Z")
I’ll second Testor’s advice to hit McMaster Carr. Be sure and get the right material (EPDM rubber) for the seal. Brake fluid eats nitrile rubber. Test the seal you bought in a small glass with brake fluid in it overnight. It is swells or melts - wrong material. ---
**Author:** ![Josephc](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@Josephc](https://community.cartalk.com/u/Josephc)\ **Post date:** [May 17, 2026, 6:54pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699/4 "2026-05-17T18:54:22Z")
Thanks for the advice. Does that type of seal have a name? Cup, follower, wiper etc.. Also following the link to mcmaster I wasn’t able to locate any seals in epdm ---
**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:** [May 17, 2026, 7:01pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699/5 "2026-05-17T19:01:37Z")
That would be a U-shaped cup seal. > **[\[Hot Item\] Hydraulic Cylinder U-Shaped Cup Piston Rod Seal Un Polyurethane PU...](https://doking.en.made-in-china.com/product/zxyYoFAHZehc/China-Hydraulic-Cylinder-U-Shaped-Cup-Piston-Rod-Seal-Un-Polyurethane-PU-Oil-Seal.html)** > > Hydraulic Cylinder U-Shaped Cup Piston Rod Seal Un Polyurethane PU Oil Seal, Find Details and Price about Oil Seal and Hydraulic Oil Seal from DOKING INDUSTRIAL LIMITED. Tester ---
**Author:** ![Josephc](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@Josephc](https://community.cartalk.com/u/Josephc)\ **Post date:** [May 17, 2026, 9:25pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699/6 "2026-05-17T21:25:51Z")
My other possible option is to swap the master cylinder out with one from another vehicle. What are the ramifications of going from a 3/4 bore up to a 7/8( which seems like about the smallest that put on cars). It is dual port and it has no vacuum assist. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [May 17, 2026, 9:43pm UTC](https://community.cartalk.com/t/brake-master-cylinder-seals-for-chinese-ev-trike/205699/7 "2026-05-17T21:43:38Z")
The larger bore would increase the pedal effort.