Author Topic: Rebooster or Debooster  (Read 704 times)

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Offline GPS

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Rebooster or Debooster
« on: Wednesday,August 21, 2024, 06:50:09 PM »
So I have a 72 twin cam. Got it about 6 months ago. Its still has the stock dual booster setup. The brake peddle when depressed went down about a couple of inches then it stopped and actuated the brakes. Not long ago I took it out the peddle went down closer to the floor before engaging the brakes.
Was going to take it out this last time and the peddle went to the floor. Now I do have brake fluid to the correct level in the MC. Not sure what type the PO used however. No leaks anywhere on brakes or outside of boosters or lines. I will try to bleed brakes and fill with recommended fluid. I am thinking worst case, new boosters. Maybe MC. Fluid is getting more discolored so I am really thinking incorrect fluid breaking down seals.??
is there a way to check the boosters? I have done a few brake systems, but nothing involving testing  a booster.
Just wondering if I should yank the boosters and bypass, or replace booster? I don't want to replumb the whole car at this point.
I have read through some of the deboostering forum chains.
Just curious the thoughts on this subject. Rebooster or Debooster.
At this point I just want to get her on the road. Any major brake upgrades will have to wait.

Offline Grumblebuns

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Re: Rebooster or Debooster
« Reply #1 on: Thursday,August 22, 2024, 09:18:18 AM »
I would first rule out that your master cylinder is not the cause of the brake problem. I would pull it out, bench bleed it then block both ports and push hard on the piston and see if it holds pressure. I have not come across any way to test the brake boosters off the the car. Rather than rebuilding the Girling booster, I would see if anyone carries the Lockheed equivalents. I loved the feel of the braking system when I had my booster working and may try to re-install them in the future.   

Online BDA

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Re: Rebooster or Debooster
« Reply #2 on: Thursday,August 22, 2024, 10:08:53 AM »
 :I-agree:

When I built my car, I knew about using a smaller M/C and deleting the brakes but because I KNEW I liked the brakes with boosters and didn't know if I'd like the increased pedal travel of the smaller M/C, I went with the Lockheed boosters. They work great. I'm very happy with them.

If I were to do it again, I MIGHT decide to go for the smaller M/C. I still have no experience with them but I've never heard of anybody who was unhappy with theirs.

Offline Pfreen

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Re: Rebooster or Debooster
« Reply #3 on: Thursday,August 22, 2024, 06:28:13 PM »
I also kept the boosters but changed to the Lockheed boosters and mounted them up front for weight balance and real estate.
I like the boosted feel a lot.
My only complaint is the f/r brake balance.  The front locks up too quickly.

Online BDA

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Re: Rebooster or Debooster
« Reply #4 on: Thursday,August 22, 2024, 07:35:02 PM »
I put mine behind the rear wheels.

I have rear discs and my fronts lock up quickly too but usually only when I’m not going very fast. I think it’s because the front is so light and in a short stop at low speed, I don’t think there’s enough weight transfer to the front for the tires to bite. They generate a lot of smoke but it doesn’t seem to flat spot them.

Offline tedtaylor

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Re: Rebooster or Debooster
« Reply #5 on: Sunday,September 22, 2024, 04:39:44 PM »
I have a pair of Lockheed boosters for sale $125 plus shipping that came out of a Europa.
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Offline Grumblebuns

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Re: Rebooster or Debooster
« Reply #6 on: Monday,September 23, 2024, 08:04:30 AM »
There are several new Lockheed brake boosters out there with different boost ratios. Anyone know what the OEM Girling booster ratio was? Were both the front and rear ratios the same?