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Thread: TR7 brake booster

  1. #1
    Jedi Knight Got_All_4's Avatar
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    TR7 brake booster

    Anybody know where to get a reasonably priced brake booster? Wedge shop is too pricey for me and noticed there are others that have rebuild kits for them. Anyone try to rebuild one and are they difficult to do?

  2. #2
    Jedi Knight
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    Re: TR7 brake booster

    They are not that hard to rebuild. Taking them apart is the tricky part. Its basically a big rubber bladder sandwiched between the two outer shells with some other seals in the middle. Sending one out to be rebuilt gets expensive because they come back all shiny and new looking. I have a shelf full of used ones if you want to take a chance with one of those. I haven't really seen them go bad unless the master cylinder starts to leak and they fill up with brake fluid. The brake fluid damages the seals and bladder. New masters are around $250.

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    Jedi Knight Got_All_4's Avatar
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    Re: TR7 brake booster

    Took some time to look at it a little closer. You can see the stains on the booster. Evidence that it may have been leaking plus the master cy. looks relatively new and I think the PO said it was recently replaced. That hissing sound is very noticeable when you push hard on the brakes and may have been part of my complaint of poor braking.
    To open it looks like you pinch the tabs out then I would imagine separating them and getting them squeezed back together to seal would be the hardest part. Still going to look around for a new one.
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    Jedi Knight Darrell_Walker's Avatar
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    Re: TR7 brake booster


    The two halves of the booster screw apart.

    What symptoms are you seeing?
    Darrell Walker
    66 TR4A IRS-SC CTC67956L
    81 TR8 SATPZ458XBA406206 (daily driver)
    Vancouver, WA, USA

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    Jedi Knight Got_All_4's Avatar
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    Re: TR7 brake booster

    I can mostly hear a hissing sound when pushing the peddle and poor breaking. When I first bought the car I complained about the hard breaking and discounted the fact that it could have been the booster, because at start up with your foot on the break the peddle moves down. It still does that but the hissing is very noticable now.

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    Jedi Knight Darrell_Walker's Avatar
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    Re: TR7 brake booster


    It could be the booster, but if the master cylinder was replaced, it could also be the seal between the cylinder and the booster wasn't transferred over (BTDT).
    Darrell Walker
    66 TR4A IRS-SC CTC67956L
    81 TR8 SATPZ458XBA406206 (daily driver)
    Vancouver, WA, USA

  7. #7
    Jedi Knight
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    Re: TR7 brake booster

    The TR7 has an inline check valve on the vacuum hose. Make sure you have it or you will get the symptoms you describe. TR7 and TR8 boosters are different in that the TR8 booster is a little bigger. In the real world you can't really notice the difference between them.

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    Jedi Knight Got_All_4's Avatar
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    Re: TR7 brake booster

    I don't see one. The vacuum line goes from the plenum (PI model) into the black inlet on the booster. Now my question would be why would I be hearing a hissing noise if the check valve is missing? I see in the Victoria British catalog that there is one available. They also have a rebuilt unit.

  9. #9
    Jedi Knight
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    Re: TR7 brake booster

    The hissing is most likely coming from where the white plastic elbow fitting pushes into the booster. If either the seal dries out or the fitting cracks, it will leak. The hose in the picture looks more like heater hose than the rigid vacuum hose. If that's the case, the constant flexing of the hose will lead to harder brakes as well. The check valve just helps keep vacuum pressure in the booster at all times, even under low vacuum situations and or repeated braking. Many of the TR8s with big cams develop low manifold vacuum pressure, which result in a very hard pedal the second time you step down on the brakes if enough time doesn't go by between pushes. Makes repeated braking in stop and go traffic difficult. A buddy of mine just installed a vacuum pump on his car that just creates vacuum for the braking system. Things may be a little different on the FI cars from what I'm used to.

  10. #10
    Jedi Knight Got_All_4's Avatar
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    Re: TR7 brake booster

    Defiantly not the heater hose unless you mean that is the type of hose they used?
    That is possible and I think what your saying there is it can't handle the vacuum and may slightly collapse effecting the braking ability? I'll have to see if I can locate a check valve too. Stopped at a local parts store today with no luck. It is also possible the elbow is leaking. It seems a little loose in the rubber grommet.
    Is there a way to check for leaks? What if I put some pressure into the hose. I would think I could hear the leaks or use a little soapy water to find them.

  11. #11
    Jedi Knight Got_All_4's Avatar
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    Re: TR7 brake booster

    Nobody has this thing. 6 Hours searching the net and a dozen phone calls again today.

  12. #12
    Jedi Knight Darrell_Walker's Avatar
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    Re: TR7 brake booster

    Quote Originally Posted by Got_All_4
    Nobody has this thing. 6 Hours searching the net and a dozen phone calls again today.
    Do you mean the check valve? Victoria British shows it.
    Attached Images Attached Images
    Darrell Walker
    66 TR4A IRS-SC CTC67956L
    81 TR8 SATPZ458XBA406206 (daily driver)
    Vancouver, WA, USA

  13. #13
    Jedi Knight
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    Re: TR7 brake booster

    PM me your address and I'll send you one.

  14. #14
    Jedi Knight Got_All_4's Avatar
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    Re: TR7 brake booster

    Darrel
    No I meant the rebuilt servo unit but I'll probably get a valve too. Found one guy that has one (rebuilt servo)but he insists it weighs 60lbs and wants to charge me some $40+ dollars to ship. I told him we can't be talking the same part because they can't weigh more then 15lb.
    I may just order a rebuild kit from VB if I think I can open it. I wanted to order new door panels too. However Saturday I'm going to stick my head under the dash and hear/see for sure that is leaking before I do anything more. Reading your responses and talking to local LBC technicians say they just don't go bad. But everything eventually wears out. 105k on mine.

  15. #15

    Re: TR7 brake booster

    ahh i wish i could help but i got very tired of all of this myself and decided to ditch the brake booster all together. although it was a bit of a project in itself, it was much cheaper and less problems, i had a series of problems ( brake master completely shot, booster needed rebuilding and pressure adj. valve was completely shot awell) and the fixing of them all added up to hours of labor, roughly $300 and all that to get me the same old TR7 braking performance that never impressed any driver. Meanwhile my GT6 has a single 5/8th inch bore master and zero booster and also breaked better than my 7. finally i decided not not spend the money to refurbish my old stuff and make a setup consisting of two brand new 7/8th bore masters ( $54 a piece ) , one to the front and one to a manual, tunr-screw adjustment valve ($19) then leads to the rear end. Shes never braked better with almost zero maintaince and i get to play around with fine tuning the rear as desired.

    If you care to see some photos:

    http://www.fineline-creations.com/Blank.html
    - '80 TR7
    - '79 Lotus Esprit S2 (My dads, I'm building )
    - '67 Datsun Roadster (My friends, Im completely rebuilding)

  16. #16
    Jedi Knight Got_All_4's Avatar
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    Re: TR7 brake booster

    Ya that baby is leaking. As soon as I push the brake pedal you can hear the vacuum. Put your fingers over one of the 4 holes in the boot and you can change the tune of the noise.
    I though about changing (updating) the braking system and was about to go to Summit Racing to see if we could adapt a better system but just ran out of $ (had to buy another car) plus I'd like to keep it as close to original as possible. Love your set up Aeroweld3033. Is that with the original size discs?

  17. #17

    Re: TR7 brake booster

    Yes it is i keep wanting to get larger ones but i really dont want larger rims
    - '80 TR7
    - '79 Lotus Esprit S2 (My dads, I'm building )
    - '67 Datsun Roadster (My friends, Im completely rebuilding)

  18. #18
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    Re: TR7 brake booster

    I just ordered a rebuilt brakebooster for my 1975 TR7. It takes approx 30 to 45 days from the time ordered until the time shipped. Price with shipping and core around $90.00.

    The company is carid and the company that remans it is a1 cardone. The part number is 53-5590. Carid phone number is 800-505-3274

    Barry

  19. #19
    Moderator Mickey Richaud's Avatar
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    Re: TR7 brake booster

    Thanks for the info, Barry, and welcome to the BCF!

    Mickey
    Mickey Richaud
    '73 MGB, '69 MGB GT/V6, Victor TF
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