Home » Public Forums » GMCnet » [GMCnet] Sensitized Boosters Leaking problem solved
| [GMCnet] Sensitized Boosters Leaking problem solved [message #235283] |
Mon, 06 January 2014 15:51  |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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Senior Member |
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There have been a lot of posts on this topic recently.
I had put in a sensitized booster many years ago that I got from Bob Lamey when he was in business in California.
I had no problem with it and it did not leak.
I later installed a P-30 master cylinder and found that I had a slow vacuum leak at the booster. Later I put in a 34mm master cylinder and still had the small leak.
The bracket for the master cylinder was put between the booster and the master cylinder instead of at the front of the master cylinder since the bracket would not fit over the front of the master cylinder. I hen used a longer push rod. Leigh Harrison does sell a bracket that will fit over the 34mm master cylinder but I did not purchase one.
When I would apply the brake pedal it would slowly sink down. My vacuum pump would also start up as soon as I applied the brakes. I didn't think too much about it until I started hearing people talk about leaking boosters.
Dave Lenzi discussed the problem at one GMCMI convention and said the rubber seal between the booster and the master cylinder which the push rod goes through often leaks when people replace the booster or the original master cylinder. I got a new seal and it helped some but still did not totally stop the leak. At the Branson GMCMI convention Dave Lenzi indicated to me that he was now machining a plastic part that would go over the "nose" of the master cylinder and press against the rubber seal. I got one from him and installed it. It worked just as Dave said it would. It provided a good seal between the rubber seal and the rear of the master cylinder.
My problem was SOLVED! No more leaking.
Dave had explained that the problem occurred when boosters or master cylinders were replaced because of the differences in the dimensions of boosters and master cylinders. He pointed out that several people have also now used metric master boosters and that the hole is about 1/2" greater than the master cylinder "nose" diameter so that when the master cylinder is bolted in place it often gets "cocked" or mis-centered and doesn't seal properly. Other times the "nose" is too short to seal properly against the booster seal. Dave says that when he provides his machined plastic part he has to know the diameter of the hole in the booster and also the outside diameter of the master cylinder "nose" that fist into the booster. There are also cases where people have lost the rubber seal when they replace their master cylinder.
Dave is planning on putting on a seminar about boosters and master cylinders at the Montgomery Texas convention. It should be a good one and I am sure it will be very enlightening one.
I think we can now tell Bob de Kruyff that all sensitized boosters DON'T leak but very ofter the connection of the rubber seal with the master cylinder does leak do to a mismatch between the dimensions of the replacement booster and/or the master cylinder.
Emery Stora
77 Kingsley
Frederick, CO
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| Re: [GMCnet] Sensitized Boosters Leaking problem solved [message #235324 is a reply to message #235288] |
Mon, 06 January 2014 23:44  |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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I'm glad to see that I'm not crazy after all (well maybe a little...). I've experienced the same exact issue with my brakes after installing the sensitized booster and 34 mm master cylinder and reaction arm system. I've been debating weather to go with a hydroboost with the diesel swap or use a more robust vacuum pump and stay with the sensitized unit.
Thank you for the head's up.
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: [GMCnet] Sensitized Boosters Leaking problem solved [message #235909 is a reply to message #235283] |
Sat, 11 January 2014 23:51 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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""I think we can now tell Bob de Kruyff that all sensitized boosters DON'T leak but very ofter the connection of the rubber seal with the master cylinder does leak do to a mismatch between the dimensions of the replacement booster and/or the master cylinder.""
No need to tell me. Gene is the one that raised the red flag. At the time, it was discovered that Sensitized boosters used vacuum while they were depressed. I think you probably have misunderstood the whole issue.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Sensitized Boosters Leaking problem solved [message #235911 is a reply to message #235283] |
Sun, 12 January 2014 00:18 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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| Emery Stora wrote on Mon, 06 January 2014 14:51 |
There have been a lot of posts on this topic recently.
I had put in a sensitized booster many years ago that I got from Bob Lamey when he was in business in California.
I had no problem with it and it did not leak.
I later installed a P-30 master cylinder and found that I had a slow vacuum leak at the booster. Later I put in a 34mm master cylinder and still had the small leak.
The bracket for the master cylinder was put between the booster and the master cylinder instead of at the front of the master cylinder since the bracket would not fit over the front of the master cylinder. I hen used a longer push rod. Leigh Harrison does sell a bracket that will fit over the 34mm master cylinder but I did not purchase one.
When I would apply the brake pedal it would slowly sink down. My vacuum pump would also start up as soon as I applied the brakes. I didn't think too much about it until I started hearing people talk about leaking boosters.
Dave Lenzi discussed the problem at one GMCMI convention and said the rubber seal between the booster and the master cylinder which the push rod goes through often leaks when people replace the booster or the original master cylinder. I got a new seal and it helped some but still did not totally stop the leak. At the Branson GMCMI convention Dave Lenzi indicated to me that he was now machining a plastic part that would go over the "nose" of the master cylinder and press against the rubber seal. I got one from him and installed it. It worked just as Dave said it would. It provided a good seal between the rubber seal and the rear of the master cylinder.
My problem was SOLVED! No more leaking.
Dave had explained that the problem occurred when boosters or master cylinders were replaced because of the differences in the dimensions of boosters and master cylinders. He pointed out that several people have also now used metric master boosters and that the hole is about 1/2" greater than the master cylinder "nose" diameter so that when the master cylinder is bolted in place it often gets "cocked" or mis-centered and doesn't seal properly. Other times the "nose" is too short to seal properly against the booster seal. Dave says that when he provides his machined plastic part he has to know the diameter of the hole in the booster and also the outside diameter of the master cylinder "nose" that fist into the booster. There are also cases where people have lost the rubber seal when they replace their master cylinder.
Dave is planning on putting on a seminar about boosters and master cylinders at the Montgomery Texas convention. It should be a good one and I am sure it will be very enlightening one.
I think we can now tell Bob de Kruyff that all sensitized boosters DON'T leak but very ofter the connection of the rubber seal with the master cylinder does leak do to a mismatch between the dimensions of the replacement booster and/or the master cylinder.
Emery Stora
77 Kingsley
Frederick, CO
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Emery, as usual, you are distorting what led up to this discussion and I don't think you have a grasp of the facts. When I originally proposed the vacuum tank as a good addition to our brake system that would allow reserve capacity in case the engine died, I was met with wide spread resistance. Many folks said that it was an inadequate solution since while the pedal was depressed, vacuum continued to be "consumed" . I led a spirited discussion that once the pedal was depressed, no vacuum should be used. After many people argued that fact, it became apparent that people with sensitized boosters actually measured that while the pedal was down, vacuum in fact was being "consumed". That led to the issue of Sensitized boosters "leaking". I think some of our reputable netters verified that issue. My reaction was that I didn't want any part of such a system. Whatever the facts may be, I have distanced myself from non engineered components and based on what OTHERS have verified, I want no part of sensitized boosters. Get your facts staight before you malign others.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Sensitized Boosters Leaking problem solved [message #235915 is a reply to message #235911] |
Sun, 12 January 2014 04:35 |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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Senior Member |
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What is your problem? I sure as hell didn't think I was maligning you. You are the one that said all sensitized boosters leak. I was pointing out that Dave Lenzi has discovered that the leak is at the connection between the booster and the master cylinder.
I guess someone who constantly has exhibited a closed mind cannot understand that.
I thought this net was for discussing problems and solutions but you apparently think it is for slamming people. There, now that I have slammed you back, I feel better.
Emery Stora
77 Kingsley
Frederick, CO
On Jan 11, 2014, at 11:18 PM, Bob de Kruyff <NEXT2POOL@AOL.COM> wrote:
>
>
> Emery Stora wrote on Mon, 06 January 2014 14:51
>> There have been a lot of posts on this topic recently.
>>
>> I had put in a sensitized booster many years ago that I got from Bob Lamey when he was in business in California.
>> I had no problem with it and it did not leak.
>> I later installed a P-30 master cylinder and found that I had a slow vacuum leak at the booster. Later I put in a 34mm master cylinder and still had the small leak.
>> The bracket for the master cylinder was put between the booster and the master cylinder instead of at the front of the master cylinder since the bracket would not fit over the front of the master cylinder. I hen used a longer push rod. Leigh Harrison does sell a bracket that will fit over the 34mm master cylinder but I did not purchase one.
>>
>> When I would apply the brake pedal it would slowly sink down. My vacuum pump would also start up as soon as I applied the brakes. I didn't think too much about it until I started hearing people talk about leaking boosters.
>> Dave Lenzi discussed the problem at one GMCMI convention and said the rubber seal between the booster and the master cylinder which the push rod goes through often leaks when people replace the booster or the original master cylinder. I got a new seal and it helped some but still did not totally stop the leak. At the Branson GMCMI convention Dave Lenzi indicated to me that he was now machining a plastic part that would go over the "nose" of the master cylinder and press against the rubber seal. I got one from him and installed it. It worked just as Dave said it would. It provided a good seal between the rubber seal and the rear of the master cylinder.
>>
>> My problem was SOLVED! No more leaking.
>>
>> Dave had explained that the problem occurred when boosters or master cylinders were replaced because of the differences in the dimensions of boosters and master cylinders. He pointed out that several people have also now used metric master boosters and that the hole is about 1/2" greater than the master cylinder "nose" diameter so that when the master cylinder is bolted in place it often gets "cocked" or mis-centered and doesn't seal properly. Other times the "nose" is too short to seal properly against the booster seal. Dave says that when he provides his machined plastic part he has to know the diameter of the hole in the booster and also the outside diameter of the master cylinder "nose" that fist into the booster. There are also cases where people have lost the rubber seal when they replace their master cylinder.
>>
>> Dave is planning on putting on a seminar about boosters and master cylinders at the Montgomery Texas convention. It should be a good one and I am sure it will be very enlightening one.
>>
>> I think we can now tell Bob de Kruyff that all sensitized boosters DON'T leak but very ofter the connection of the rubber seal with the master cylinder does leak do to a mismatch between the dimensions of the replacement booster and/or the master cylinder.
>>
>> Emery Stora
>> 77 Kingsley
>> Frederick, CO
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> Emery, as usual, you are distorting what led up to this discussion and I don't think you have a grasp of the facts. When I originally proposed the vacuum tank as a good addition to our brake system that would allow reserve capacity in case the engine died, I was met with wide spread resistance. Many folks said that it was an inadequate solution since while the pedal was depressed, vacuum continued to be "consumed" . I led a spirited discussion that once the pedal was depressed, no vacuum should be used. After many people argued that fact, it became apparent that people with sensitized boosters actually measured that while the pedal was down, vacuum in fact was being "consumed". That led to the issue of Sensitized boosters "leaking". I think some of our reputable netters verified that issue. My reaction was that I didn't want any part of such a system. Whatever the facts may be, I have distanced myself from non engineered components and based on what OTHERS have verified, I
w
> ant no part of sensitized boosters. Get your facts staight before you malign others.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Sensitized Boosters Leaking problem solved [message #236021 is a reply to message #235915] |
Sun, 12 January 2014 20:24 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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I think you both should log on and play call of duty black ops against each other.
Todd Sullivan
Sully
77 royale
Seattle
> On Jan 12, 2014, at 2:35 AM, Emery Stora <emerystora@me.com> wrote:
>
> What is your problem? I sure as hell didn't think I was maligning you. You are the one that said all sensitized boosters leak. I was pointing out that Dave Lenzi has discovered that the leak is at the connection between the booster and the master cylinder.
>
> I guess someone who constantly has exhibited a closed mind cannot understand that.
>
> I thought this net was for discussing problems and solutions but you apparently think it is for slamming people. There, now that I have slammed you back, I feel better.
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>
>> On Jan 11, 2014, at 11:18 PM, Bob de Kruyff <NEXT2POOL@AOL.COM> wrote:
>>
>>
>>
>> Emery Stora wrote on Mon, 06 January 2014 14:51
>>> There have been a lot of posts on this topic recently.
>>>
>>> I had put in a sensitized booster many years ago that I got from Bob Lamey when he was in business in California.
>>> I had no problem with it and it did not leak.
>>> I later installed a P-30 master cylinder and found that I had a slow vacuum leak at the booster. Later I put in a 34mm master cylinder and still had the small leak.
>>> The bracket for the master cylinder was put between the booster and the master cylinder instead of at the front of the master cylinder since the bracket would not fit over the front of the master cylinder. I hen used a longer push rod. Leigh Harrison does sell a bracket that will fit over the 34mm master cylinder but I did not purchase one.
>>>
>>> When I would apply the brake pedal it would slowly sink down. My vacuum pump would also start up as soon as I applied the brakes. I didn't think too much about it until I started hearing people talk about leaking boosters.
>>> Dave Lenzi discussed the problem at one GMCMI convention and said the rubber seal between the booster and the master cylinder which the push rod goes through often leaks when people replace the booster or the original master cylinder. I got a new seal and it helped some but still did not totally stop the leak. At the Branson GMCMI convention Dave Lenzi indicated to me that he was now machining a plastic part that would go over the "nose" of the master cylinder and press against the rubber seal. I got one from him and installed it. It worked just as Dave said it would. It provided a good seal between the rubber seal and the rear of the master cylinder.
>>>
>>> My problem was SOLVED! No more leaking.
>>>
>>> Dave had explained that the problem occurred when boosters or master cylinders were replaced because of the differences in the dimensions of boosters and master cylinders. He pointed out that several people have also now used metric master boosters and that the hole is about 1/2" greater than the master cylinder "nose" diameter so that when the master cylinder is bolted in place it often gets "cocked" or mis-centered and doesn't seal properly. Other times the "nose" is too short to seal properly against the booster seal. Dave says that when he provides his machined plastic part he has to know the diameter of the hole in the booster and also the outside diameter of the master cylinder "nose" that fist into the booster. There are also cases where people have lost the rubber seal when they replace their master cylinder.
>>>
>>> Dave is planning on putting on a seminar about boosters and master cylinders at the Montgomery Texas convention. It should be a good one and I am sure it will be very enlightening one.
>>>
>>> I think we can now tell Bob de Kruyff that all sensitized boosters DON'T leak but very ofter the connection of the rubber seal with the master cylinder does leak do to a mismatch between the dimensions of the replacement booster and/or the master cylinder.
>>>
>>> Emery Stora
>>> 77 Kingsley
>>> Frederick, CO
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>> Emery, as usual, you are distorting what led up to this discussion and I don't think you have a grasp of the facts. When I originally proposed the vacuum tank as a good addition to our brake system that would allow reserve capacity in case the engine died, I was met with wide spread resistance. Many folks said that it was an inadequate solution since while the pedal was depressed, vacuum continued to be "consumed" . I led a spirited discussion that once the pedal was depressed, no vacuum should be used. After many people argued that fact, it became apparent that people with sensitized boosters actually measured that while the pedal was down, vacuum in fact was being "consumed". That led to the issue of Sensitized boosters "leaking". I think some of our reputable netters verified that issue. My reaction was that I didn't want any part of such a system. Whatever the facts may be, I have distanced myself from non engineered components and based on what OTHERS have verified,
I
> w
>> ant no part of sensitized boosters. Get your facts staight before you malign others.
>> --
>> Bob de Kruyff
>> 78 Eleganza
>> Chandler, AZ
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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