2003 Hydro Boost Swap Question …

dps01 · Mar 28, 2024

Lots of information on forums regarding swapping vacuum assist to hydro boost braking system.

I know that the hydro boost brake pedal is different than the vacuum assist brake pedal and must be used in the swap.

Do vehicles with adjustable pedals (JF4) use the same brake pedals as the non adjustable vehicles (depending upon the assist method) ? Or is there yet another version of the brake pedal for JF4 equipped vehicles?

I have not come across a JF4 hydro boost equipped vehicle in a bone yard to compare…(yet)

Apologize in advance if this question has already been answered…

rockola1971 · Mar 30, 2024

dps01 said:
Lots of information on forums regarding swapping vacuum assist to hydro boost braking system.

I know that the hydro boost brake pedal is different than the vacuum assist brake pedal and must be used in the swap.

Do vehicles with adjustable pedals (JF4) use the same brake pedals as the non adjustable vehicles (depending upon the assist method) ? Or is there yet another version of the brake pedal for JF4 equipped vehicles?

I have not come across a JF4 hydro boost equipped vehicle in a bone yard to compare…(yet)

Apologize in advance if this question has already been answered…

You are in luck. I have a 05 Yukon Denali and (2) 03 Tahoe LT's. Denali has Hydroboost. What is it that you need to see or know about the brake pedals?

dps01 · Mar 31, 2024

I am looking for the relative position of the stud on the brake pedal that connects to the master cylinder assist.

I have a vacuum assist set up with adjustable pedals. Trying to ascertain if the brake pedal design for hydro boost is the same for both adjustable and non adjustable pedals. I know it is different between vacuum and hydro boost.

See attached from GMFS.

project_x · Mar 31, 2024

I can take some pics. I have a JF4 equipped Yukon Denali that I am stripping. I have everything out of the interior except the pedals, so can take a few pics and make some measurements.

dps01 · Apr 1, 2024

@project_x that would be appreciated.

project_x · Apr 2, 2024

dps01 said:
@project_x that would be appreciated.

I will try to get some pics tomorrow.

Burban22 · Jun 2, 2026

I have an 03 burb with vacuum brakes and picked up a wrecked 05 burb I’m using for an LS swap on my 84 Wagoneer.

Was going to put the Hydroboost in my 03 but is the upgrade worth all the work? My vacuum brakes work pretty good but it could always be better. Did you notice a big difference?

This guy did a video where he had to cut the firewall, but he was using a 2002. Will I have to do all these modifications on my 2003?

Fless · Jun 3, 2026

Burban22 said:
I have an 03 burb with vacuum brakes and picked up a wrecked 05 burb I’m using for an LS swap on my 84 Wagoneer.

Was going to put the Hydroboost in my 03 but is the upgrade worth all the work? My vacuum brakes work pretty good but it could always be better. Did you notice a big difference?

This guy did a video where he had to cut the firewall, but he was using a 2002. Will I have to do all these modifications on my 2003?

I think the hydroboost is a good improvement, but more work than replacing the front brakes with those from a GMT900.

2003 Hydro Boost Swap Question …

dps01

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rockola1971

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dps01

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project_x

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dps01

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Burban22

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