JCB Brake Seal & Wheel Cylinder Issues
Applies to: JCB 3DX / 4DX
Quick answer
JCB Brake Seal & Wheel Cylinder Issues on JCB 3DX / 4DX: typical warning signs include Pedal spongy or low; Oil at brake drums. Common causes include Seal hardening; Cylinder bore scoring. These notes identify parts to quote — they are not a certified repair procedure.
- Independent OEM-compatible supplier — not affiliated with JCB Ltd.
- Workshops typically RFQ: wheel cylinder.
- Workshops typically RFQ: brake seal kit.
- Workshops typically RFQ: master cylinder kit.
Warning signs
- Pedal spongy or low
- Oil at brake drums
- Pulling on application
- Air after bleed attempts
Common causes
- Seal hardening
- Cylinder bore scoring
- Contaminated brake fluid
- Improper bleed sequence
Parts to quote
Typical line items workshops search next to this fault. Matched catalogue links go to a verified SKU when found; otherwise open search so you can RFQ by keyword. We confirm fitment before quoting.
More symptom pages: Failure guides
FAQ
Do you supply full axle brake kits?▼
Yes — list axle side, serial range, and drum type on your RFQ for a matched kit quote.
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Confirm fitment & get a quote
Send machine model, hours, and part photos. We reply with availability, MOQ, and lead time in writing — no invented stock claims.