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Ford F150 Starter Bolt Size

Ford F150 Starter Bolt Size

Ford F150 has starter motors compatible with its different engine variants to initiate the engine movement before its starts. There are 2-3 bolts to fix the F150 starter motors with the engine in its place. It has mounting holes on the transmission bellhousing that aligns with its collar holes to secure it in its place.

Ford F150 starter bolt size is M8x1.25x35mm in metric units for the 2004-2008 models with the 5.4-liter V8 engine. Other options are M10 and M12 bolts with 13mm hex heads. Another commonly used size is ⅜” -16 x 1 ½” for the 1997-2004 F150 with 4.2-liter V6 engines. They require 13mm and 9/16 inches sockets to remove or install them. You must check for the compatible size of bolts with your truck model and buy OEM parts for perfect fitment to prevent any damage.

This article will guide Ford truck owners regarding compatible starter bolts for its installation. We will also discuss other aspects like its importance, the size of tools required, and methods to prevent or remove the snapped bolts. 

Purpose of starter bolt on Ford F150

The purpose of a motor starter with the Ford F150 engine is to crank the engine before ignition starts.

Therefore, it requires high torque to initiate the movement of such a powerful engine crankshaft. A set of bolts secure the starter in its place after the alignment of pinion gear with the engine flywheel.

Due to high initial torque requirements, a starter motor should be firm in its place. Therefore, we install appropriate size bolts torqued according to recommended settings to fix the starter with the transmission body.

If you don’t install it properly or cross thread it, it can damage the mounting holes and, in some cases, damage the transmission case resulting in leakage of its fluid.

Moreover, keeping them loose can also result in breakage of its body while applying torque to the flywheel.

How many bolts are on the starter motor for Ford F150?

The starter motor is an automobile part, specific for the Ford F150 engine, according to the initial torque requirements to crank it.

Therefore, its design, shape, gear ratio, and mounting holes can vary according to the engine installed on the truck. For F150, there are starter motors with mounting positions for 2-3 bolts.

Earlier small block engines have 2 bolts, while later engines have compatible starters with 3 bolts. Therefore, the minimum requirement for its proper installation is 2 bolts.

Even if you use 2 bolts of suitable size on a 3 bolt starter and torque it properly, it is sufficient to hold it in its place without any breakage or loosing of the starter.

It is better to check the starter design compatible with the Ford F150 engine and install all the bolts according to the mounting holes available.

Besides mounting these, there are 3 more bolts on every starter to install the power supply from the battery, a solenoid control signal, and a ground wire attached to its body. 

What is the starter bolt size for Ford F150?

Most of the latest truck engines have 3 bolts of 13mm hex heads to mount their starter on the transmission bell housing.

However, specific sizes depend on the particular engine option and its compatible starter motor. Ford F150 from the 2001-2005 model has 3 bolts of 13mm head.

The power source from the battery and ground is also secured by a 13mm bolt, while the size for solenoid wires is 10mm each.

The actual diameter of its threaded portion is 10mm in metric units, while in SAE units, it is ⅜ inches. Its length can vary from 1.5 inches to 2.5 inches. In case of excess length, you can clip it for perfect fitment. 

Starter compatible with Ford 5.4-liter V8 from 1997-2003 and its 3 valve version from 2004-2010 models has M8x1.25x35mm bolt size. Its nominal diameter for the threaded part is 8mm, and the thread pitch is 1.25mm.

The bolt length is 35mm (1.38 inches), and its drive or head size is 13mm (0.51 inches). The same is also the pattern for 1997-2010 for 4.6-liter V8 engines in F150 pickup trucks.

Ford F150 with 5.0-liter engine starter bolts are ⅜” in thread diameter, ½” thread length, and 2″ in bolt length.

For the 4.2-liter V6 engine in 1997-2004 models have ⅜” -16 bolts and have a length of 1.5″ in SAE units.

They have a thread diameter of ⅜” (9.52mm), and the number of threads is 16. Bolts have a length of 1-½” (38.1mm) that is sufficient to hold them with the transmission body.

Its head size is 9/16″ (14.29mm). It is also not fully threaded and has flat shoulders. Instead, you can buy steel bolts with zinc coating to prevent corrosion and enhance their life.

There are also OEM bolts compatible with the starter motor of the 2011-2014 model Ford F150 3.5-liter V6 EcoBoost engine and 2021 2.7-liter V6, 3.3-liter V6, and 3.5-liter V6 PowerBoost. You can find it by entering its specific part number. 

2006 model with 5.4-liter Triton has 2 bolts and a stud to tie ground wire. The stud has M8x1.25×30 dimensions. Bolts have an M8x1.25×41 size having an 8mm diameter, 1.25mm thread pitch, and 41mm length.

The 1990 Ford F250 with a 7.3-liter IDI diesel engine has a bolt size of 10mm diameter, 1.25mm pitch, coarse thread, and 13mm hex head. Its length is 2-inches. Similarly, for 2002 Ford F250 7.3-liter has 2 bolts of M10 x 1.5 x 35mm and class 8.8.

1994 Ford F350 7.5-liter has starter bolts of 3/8″ diameter, 16 threads, and X3″ in length.

What size tools to remove the starter bolt on Ford F150?

You need a socket wrench with a standard socket set and an extension kit to access the starter bolts. On a 3 bolts pattern, the first bolt is easy to remove because it is visible.

For the 2nd and 3rd ones, you have to use a 6″ long extension kit with the wrench and open them by feeling them with your hand. 2 commonly used bolt sizes are ⅜” in SAE and M8 or M10 in metric units.

Therefore, you will need a 9/16″ or 13mm hex socket to remove or install the starter bolts. A 10mm socket can remove the solenoid wire terminal.

In some cases, their size can deviate from standard sizes as somebody may have used other than OEM bolts while replacing them. Therefore, you should make sure of its dimensions before going for removal. 

I recommend using a ½” drive ratchet or socket wrench to remove the bolts easily. You can also use a ¼” ratchet. However, the smaller drive can require more force, and larger ratchets will not fit and maneuver well due to space constraints.

Torque requirements of starter bolt on Ford F150

Proper torquing of these bolts and power terminals is essential for proper operation. Too tightening can damage their threads and also cause cracks in transmission bellhousing.

While too loose bolts can result in deviation of the starter from its place and further loss to its gears and transmission body.

Torque requirements for the 3 bolts to hold the starter are 22-27 Nm (16- 20 ft-lbs). First, you should torque the power cable from the battery’s positive terminal to 11-13 Nm (8-10 ft-lbs).

Next, you should apply the torque to the solenoid cable 5-7 Nm (3.7-5 ft-lbs). If you don’t have a torque wrench available, you should tighten them until they are snug to ensure proper installation.

What are the causes of broken starter bolts?

Several factors are causing the starter bolts to break or snap within the transmission body. If you install improperly sized bolts, they will be too loose or tight, resulting in breakage.

Another most obvious reason is the wear and tear due to corrosion causing them to become weak with time. When you apply force to remove them, they can break.

Therefore, I have always suggested customers use any spray like WD-40 to soften them before removal. Another factor is the low-grade material of the bolts causing them to snap.

Therefore, always use 8-grade steel bolts protected by anti-rust coating for longer life. Making them too tight or installing them in a cross-thread pattern can also damage their body resulting in their breakage over time.

Improper alignment or losing 1 or 2 mounting bolts holding the starter can cause extra stress on the remaining one, which can snap during starting.

Moreover, if its pinion does not disengage after the engine starts, very high speeds can also make it bear the damage.

Why should you know the Ford F150 starter bolt size?

Starter mounting holes are on the transmission bellhousing or its body. Moreover, the spots on its mounting bracket are bigger than the ones on the transmission body with threads to align its pinion with the flywheel gears.

Therefore, you should consider the thread size of starter bolts for their proper installation.

If you select the ones with smaller diameters, they will be loose and soon come off their place. In severe cases, it can result in catastrophic damage to the starter motor and transmission housing.

Moreover, oversized bolts will not accurately fit in their mounting holes without damaging their inner threads.

It can result in permanent damage, and you have to replace the transmission cover.

Furthermore, you should also select high-grade aluminum or steel bolts with heat treatment and protective coating for durable operation.

How to remove a broken starter bolt on Ford F150?

Sometimes, when you try to remove rusted, worn out, or improperly installed starter bolts on Ford F150, they can snap, resulting in a part of their body strangled inside the transmission housing.

You have to be careful and skillfully try these methods to remove the broken pieces to prevent damage to these parts.

A propane torch can heat the transmission casing over the mounting holes causing it to expand, and a broken bolt will come out.

Another method will be to drill a hole with a smaller bit in the broken piece and try to remove it by inserting an Allen key.

If any bolt has a broken head, you can use a stud remover tool to extract it. General practice is to immerse it with oil or any spray to make it soft and loosen over time.

Does the starter bolt size remain the same for Ford F150, F250, and F350?

The bolt size varies according to the engine type and its compatible starter motor. However, there are a few commonly used sizes like M8 and M10 in metric dimensions and ⅜ inches in SAE units.

But their length can vary according to the truck engine. Therefore, you should ensure the size of mounting bolts is compatible with the particular model year and installed engine options for Ford F150, F250, and F350.

I have always preferred buying OEM starter bolts by checking their vehicle fitment.

Does starter bolt size depend on the Ford F150 engine size?

Yes, you will always find the starter mounting bolt dimensions compatible with specific engine options.

Furthermore, you will find their compatibility mentioned against the type of engines available in pickup trucks.

It is because each of them has its compatible starter motor, and its design and shape are also specific.

Moreover, transmission bellhousing is also distinctive for engine options.

How much does a starter bolt cost for Ford F150?

Starter bolts are inexpensive items, and their prices vary according to their grade and material of construction.

For example, you can buy a ⅜” -16 x1 ½” bolt with a steel body and zinc coating for $0.3-$0.4 per piece.

M8 x1.25 x 35 bolt has a price of $0.8-$1.0 with 8.8 class and zinc coating. Furthermore, you can buy OEM bolts compatible with the 2011-2014 and 2021 Ford F150 for $2.3-$3.0 per item.

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