diff --git a/packages/api/src/clients/vehicles.ts b/packages/api/src/clients/vehicles.ts
index 9a18810..c667ec0 100644
--- a/packages/api/src/clients/vehicles.ts
+++ b/packages/api/src/clients/vehicles.ts
@@ -20,6 +20,10 @@ function buildVehicleFormData(payload: Record<string, any>): FormData {
         if (value == null) continue
         if (value instanceof File) {
             fd.append(key, value)
+        } else if (typeof value === "boolean") {
+            // Laravel's `boolean` rule rejects the strings "true"/"false";
+            // serialize as "1"/"0" so multipart payloads validate correctly.
+            fd.append(key, value ? "1" : "0")
         } else {
             fd.append(key, String(value))
         }