E36/E46 M14 Bolt Upgrade for (non-M) Polyurethane Front Differential Mount Bushing - Fits E85 and E86

Overview

If you're an avid track racer or drift enthusiast, chances are you may have had to deal with more than a few weak stock bolts, especially those that hold your bushings together! Engineered to withstand the rigors of aggressive driving, this front diff bolt upgrade is a game-changer for those seeking added strength and peace of mind for your non-M E36, E46, or Z4 without the need to tap and drill the threaded holes on your differential.

Say hello to our Garagistic M14 Bolt Upgrade - a tried and tested solution to weak stock diff bolts! With a 14mm shank and threads that match the factory thread pitch of the holes on your differential, M12x1.5, our diff bolts are a fantastic upgrade that improves on both overall strength and fitment, while also not requiring you to drill and tap your differential to M14. Made using class 12.9 steel, it boasts remarkable tensile strength, standing at least 25% stronger than the mediocre medium-strength steel screws used in stock bolts. This impressive enhancement in strength ensures that the bolt can handle the aggressive forces encountered on the track, offering you unmatched durability and performance.

Many BMW enthusiasts involved in track racing, drifting, or spirited driving have experienced the headache of stock bolts snapping under intense driving conditions. While suitable for regular driving, the factory bolts are beginning to show their age and often fail to handle the increased stress and forces encountered during high-performance maneuvers. This can lead to catastrophic consequences, leaving drivers stranded and putting their safety at risk.

We highly recommend pairing our M14 bolt with our Garagistic M14 front differential mount bushings! We sell a combo of bushing + bolt which you can purchase here! (Will also work with other aftermarket M14 front diff bushings)

Why not just get a higher-grade bolt?

First of all, you are free to buy a replacement bolt if you think it's just as good. You won't be able to find one that has the correct specs because we obviously tried to do that before we bothered to make our own bolt. The closest hardware out there still had a standard nominal shoulder size that left room for the bushing to move. Precision shoulder bolts get expensive and don't have the grade (or cost) to upgrade effectively.

The force that breaks a differential bolt is the allowance of movement between a differential bushing and the hardware that holds it. The sloppier the fit, the more movement is allowed which is what causes the clunk and eventually the bolt failure (see this a lot in clutch-kicking drift cars).

Although a higher grade is an upgrade itself over the OEM bolt, it's the movement between the bolt and diff hole that allows the diff to move. This accelerating force of the diff nose being able to move up and down is what causes bolts to break.

The M14 upgrade is something that's been tried and true by racers and drifters for a long time. We didn't invent that. Although the shoulder being bigger in diameter adds strength itself, the weak point is still the beginning of the threads. What the 14mm shoulder in our hardware achieves is that it's a tighter fit into the bushing which stops the diff from moving under heavy load (like clutch kicking etc). 

Is this as strong as an M14 bolt all the way through? No. The threads are bigger on a standard M14 bolt, but to run a standard M14 bolt you will be required to drill and tap the OEM threaded holes on your diff to M14, which can be frustrating as these diffs are getting rarer and harder to find. Not to mention the amount of people who mess this up is pretty impressive. 

So we simply took the time and money to develop something we think the market would benefit from at a VERY affordable price. A little piece of mind and a slight upgrade over the OEM bolt without the need to drill and tap your diff.

Cliff notes: The tighter fit between the 14mm shoulder of our bolt and the 14mm hole in our bushings is what is helping with sheer strength more than the higher grade of hardware.

Features

• Shank Thickness: 14mm
• Thread Pitch: M12x1.5 (Same as OEM threaded holes on differential)
• Bolt Grade: 12.9
• Coating: Clear Zinc Coated (for rust prevention)

Requirements by Chassis

E36 chassis (except Ti) will require 1x of these bolts

E46 (non-M) chassis will require 2x of these bolts

Z4 (non-M) chassis will require 2x of these bolts

Fitment

WHAT MODEL CARS WILL THIS BOLT FIT?

• Replaces: Direct replacement for OEM Bolt PN#33176760337
• Fits: E36 chassis (All Models, EXCEPT Ti)
• Fits: E46 chassis (All Models, Except M cars)
• Fits: E85 and E86 Z4 chassis (All Models, Except M cars)
  
• Note: Does NOT require threaded differential holes to be drilled and tapped to M14