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Old 04-13-2016, 07:17 AM   #1
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Join Date: Feb 2016
Location: London
Posts: 79
How to: Replace brake master cylinder and booster / servo (with video)

Spent the weekend rebuilding the braking system and swapped out the master cylinder and booster.

Step by step video is here:

Here’s a summary of what we’ll be doing
Remove plastic bits
Move horn
Remove reservoir
Disconnect brake lines
Remove master cylinder
Disconnect brake pedal linkage
Remove brake booster
Fit new booster and master cylinder
Bleed the brakes and clutch

Tools and parts needed
• Knife
• Scissors
• Socket set
• Snips
• Pliers
• Screwdrivers
• Turkey baster
• Plastic Cup
• Plastic bags
• Flare spanner (13mm)
• Breaker bar
• New Brake master cylinder
• And a new Brake booster

1. Lift the bonnet and remove the plastic covering the brake fluid reservoir, master cylinder and booster. It’s held on with one bolt and one screw.

2. Then unscrew and remove this plastic piece and unclip the battery cover.

3. We need to move the horn out of the way so remove the lower nut holding it in place and move it to one side.

4. This is the black tubing that covers the brake pedal linkage. We’ll need to remove this so cut the tubing down the middle with a knife, remove the ties holding it in place at each end and pull it out.

5. Put down a towel then remove the brake fluid reservoir cap and filter. Using a turkey baster suck out all the fluid into a cup.

6. Unclip the brake fluid sensor then pull up on the reservoir to remove it. A plastic bag can be used to catch any drips of fluid. My car is an automatic but if you have a manual car then there will be a clutch line connected to the reservoir you’ll need to remove too.

7. We can now start disconnecting the two brake lines that connect to the master cylinder. Using a 13mm flare spanner loosen the nut on the first line, remove from the cylinder and pop a plastic bag over to catch any drips. The nut on the other line just needs loosening.

8. The master cylinder is held on with two 22 mil nuts - One at the top right and one bottom left. A breaker bar can make your life easier removing these. The master cylinder will now simply pull straight out.

9. Now we start removing the brake booster. Pull the vacuum hose out then unscrew and remove the two very long bolts holding it in. They are torx 45.

10. You will now need to remove the booster from the brake pedal linkage. The pedal linkage nut is here as is 17 mil. The locking nut is here and is 19 mil

11. Using both a 17 and 19 mil spanner place them on the two nuts as shown and break them loose.

12. Now it’s important not to move the position of the locking nut. Why? Well, I’ll explain. The locking nut determines how far the booster screws into the pedal linkage and thus affects the brake pedal height. If the pedal height is altered too much then the pedal won’t touch the brake light switch and the switch isn’t pressed then your brake lights will permanently stay on.

13. Holding the nut with the 17 mil spanner unscrew the booster.

14. To remove the booster you’ll need to move the amplifier out of the way – unscrew the other bolt holding it in then remove the two screws holding this trim piece in. Avid views may already know I removed the factory cd player to save weight a while ago so if you still have yours this will need unscrewing too.

15. Next move the upper brake line behind the booster then gently lift the booster out.

16. Peel the old gasket off.

17. So here’s the new booster. It comes with a cap on it we don’t need so using two spanners break it loose and unscrew it.
18. The new booster comes with a new black tubing. Remove it and make a cut along it.

19. Now, remember I said not to move the position of the locking nut on the original booster? We’ll now you need to line up both the original and new booster and rotate the locking nut on the new booster so that it’s in the same position as the original.

20. Fitting the new booster is the reverse of the removal process.. Simply fit it back onto the car, connect up the pedal linkage to the booster and lock it tight with the locking nut using two spanners.

21. Re-fit the black tubing and secure it with two cable ties.

22. Here is the brake booster. Inside it you can see a rod. When fitting the new master cylinder make sure you insert it so that the rod fits inside it.

23. From this point on re-fitting everything is simply the reverse of the removal process.

24. Once all back together the brakes and clutch will need bleeding.

25. As the master cylinder is new it will be full of air. Some people bench bleed the cylinder before fitting but I didn’t need to. Click the screen now to see my guide on how to bleed your brakes. To get all the air out of the master cylinder follow my guide but increase the number of times you press and release the brake pedal. In the guide I do this once per bleed valve but I would suggest increasing this to 8 times per valve to make sure all trapped air is released.

26. Go for a test drive and if the pedal is spongy you’ve not got all the air out and will have to bleed again.

neil_b is offline   Reply With Quote
Old 04-15-2016, 09:42 AM   #2
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Join Date: Aug 2015
Location: Boise, ID
Posts: 81
Thanks for these videos...I hope I never have to use them.
thatguychad is offline   Reply With Quote
Old 04-15-2016, 12:09 PM   #3
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Join Date: Feb 2016
Location: London
Posts: 79
Originally Posted by thatguychad View Post
Thanks for these videos...I hope I never have to use them.
you are very welcome

neil_b is offline   Reply With Quote

booster , brakes , guide , master cylinder , servo

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