Booster Clevis Pin problems

[Kelvin]

I'm installing a new brake booster. I've cut away enough of the
under-dash to get at all of the bolts. Got the Master Cylinder tied up
out of the way. I'm trying to remove the clevis pin that connects
booster to brake pedal "arm". It is NOT coming out. I couldn't get it
to spin so removing the cotter pin was a real chore, too. I've tapped
on the free end of the pin a bit but haven't really whacked it yet.

It seems to be stuck in the brake pedal arm "Y" part of the assembly.
The booster rod itself will move sideways on the pin but the pin won't
move in the "Y" of the brake pedal arm.

Is this a thing? PB Blaster and more tapping? I don't want to damage
the "Y" shape and make things really difficult to re-assembly.

Kelvin
'73 23' in Eugene, OR

 

[Ken H.]

Kelvin,

Can you watch the pin while gently moving the brake pedal? If so, do the
Yoke and Pin move simultaneously? In other words, is it possible that the
pin is worn so badly that there's a step in it locking it into the Y?

Any way you can get pliers onto the (admittedly tiny) head of the Pin to
rotate it, either freeing its corrosion or displacing the step? Certainly
PB Blaster, Kroil, or ATF+Acetone can't hurt.

Aside from fabricating a "Pin Pusher" from a C-clamp, that's about all I
can think of. The location certainly doesn't make it easy, even with a
free Pin.

Ken H.

> I'm installing a new brake booster. I've cut away enough of the
> under-dash to get at all of the bolts. Got the Master Cylinder tied up out
> of the way. I'm trying to remove the clevis pin that connects booster to
> brake pedal "arm". It is NOT coming out. I couldn't get it to spin so
> removing the cotter pin was a real chore, too. I've tapped on the free end
> of the pin a bit but haven't really whacked it yet.
>
> It seems to be stuck in the brake pedal arm "Y" part of the assembly. The
> booster rod itself will move sideways on the pin but the pin won't move in
> the "Y" of the brake pedal arm.
>
> Is this a thing? PB Blaster and more tapping? I don't want to damage the
> "Y" shape and make things really difficult to re-assembly.
>

 

[Kelvin]

I managed to get it free with a properly shaped drift. Couldn't get a
straight shot at it so I notched it to help grab the edge of the pin.

The yoke isn't wallered out that I can tell. The pin was just stuck in
there. And there's no obvious corrosion, either. I'll be test fitting
parts before they go back together. No room in there to mess around
will ill-fitting bits.

Kelvin

> Kelvin,
>
> Can you watch the pin while gently moving the brake pedal? If so, do the
> Yoke and Pin move simultaneously? In other words, is it possible that the
> pin is worn so badly that there's a step in it locking it into the Y?
>
> Any way you can get pliers onto the (admittedly tiny) head of the Pin to
> rotate it, either freeing its corrosion or displacing the step? Certainly
> PB Blaster, Kroil, or ATF+Acetone can't hurt.
>
> Aside from fabricating a "Pin Pusher" from a C-clamp, that's about all I
> can think of. The location certainly doesn't make it easy, even with a
> free Pin.
>
> Ken H.
>
>

>
>> I'm installing a new brake booster. I've cut away enough of the
>> under-dash to get at all of the bolts. Got the Master Cylinder tied up out
>> of the way. I'm trying to remove the clevis pin that connects booster to
>> brake pedal "arm". It is NOT coming out. I couldn't get it to spin so
>> removing the cotter pin was a real chore, too. I've tapped on the free end
>> of the pin a bit but haven't really whacked it yet.
>>
>> It seems to be stuck in the brake pedal arm "Y" part of the assembly. The
>> booster rod itself will move sideways on the pin but the pin won't move in
>> the "Y" of the brake pedal arm.
>>
>> Is this a thing? PB Blaster and more tapping? I don't want to damage the
>> "Y" shape and make things really difficult to re-assembly.
>>
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> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Jim Hupy]

Kelvin, those pins are a bitch. No easy way. That whole vacuum booster
assembly had to be engineered by someone who NEVER INTENDED TO BE THE ONE
WHO HAD TO WORK ON IT. VERY TYPICAL OF GM engineers during the 70's and
80's who had little or no practical hands on experience. I worked on those
vehicles and cussed those guys daily. The dash and windshields had to be
not installed when the booster and linkage were installed. Sounds like you
found a way, though.
Jim Hupy

> I managed to get it free with a properly shaped drift. Couldn't get a
> straight shot at it so I notched it to help grab the edge of the pin.
>
> The yoke isn't wallered out that I can tell. The pin was just stuck in
> there. And there's no obvious corrosion, either. I'll be test fitting
> parts before they go back together. No room in there to mess around will
> ill-fitting bits.
>
> Kelvin
>
>

>
>> Kelvin,
>>
>> Can you watch the pin while gently moving the brake pedal? If so, do the
>> Yoke and Pin move simultaneously? In other words, is it possible that the
>> pin is worn so badly that there's a step in it locking it into the Y?
>>
>> Any way you can get pliers onto the (admittedly tiny) head of the Pin to
>> rotate it, either freeing its corrosion or displacing the step? Certainly
>> PB Blaster, Kroil, or ATF+Acetone can't hurt.
>>
>> Aside from fabricating a "Pin Pusher" from a C-clamp, that's about all I
>> can think of. The location certainly doesn't make it easy, even with a
>> free Pin.
>>
>> Ken H.
>>
>>

>>
>> I'm installing a new brake booster. I've cut away enough of the
>>> under-dash to get at all of the bolts. Got the Master Cylinder tied up
>>> out
>>> of the way. I'm trying to remove the clevis pin that connects booster to
>>> brake pedal "arm". It is NOT coming out. I couldn't get it to spin so
>>> removing the cotter pin was a real chore, too. I've tapped on the free
>>> end
>>> of the pin a bit but haven't really whacked it yet.
>>>
>>> It seems to be stuck in the brake pedal arm "Y" part of the assembly.
>>> The
>>> booster rod itself will move sideways on the pin but the pin won't move
>>> in
>>> the "Y" of the brake pedal arm.
>>>
>>> Is this a thing? PB Blaster and more tapping? I don't want to damage
>>> the
>>> "Y" shape and make things really difficult to re-assembly.
>>>
>>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Kelvin]

> Kelvin, those pins are a bitch. No easy way. That whole vacuum booster
> assembly had to be engineered by someone who NEVER INTENDED TO BE THE ONE
> WHO HAD TO WORK ON IT. VERY TYPICAL OF GM engineers during the 70's and
> 80's who had little or no practical hands on experience. I worked on those
> vehicles and cussed those guys daily. The dash and windshields had to be
> not installed when the booster and linkage were installed.

Very obvious that was the case. They COULD have left some room to work
on them if they thought it thru. My guess there were a lot of things
they did thing thru and ran out of time to work out every detail.

So what takes the place of the Power Level controls on a Electro Level
coach? Without having access thru that area I can't see how it would be
done without mangling the dash.


> Sounds like you found a way, though.

So far. It's mostly back together but this is a Lenzi booster so it has
two vacuum ports. Putting a check valve in place in the second one and
I find the 34mm MC reservoir comes in contact with the valve.

Can I rotate the Booster 180° to put those vacuum ports at the bottom?
I can't see how vacuum has an up or down but don't know what's really in
that booster. It's symmetrical on the outside!

Kelvin

 

[Jim Hupy]

The later coaches without air knobs in the dash have a lower section that
gives a bit of access when removed. The heater controls can also be removed
after the bezel plate is taken off. Still, no walk in the park. Pisses me
off every time I work on a booster.
Jim Hupy

> Kelvin, those pins are a bitch. No easy way. That whole vacuum booster
> assembly had to be engineered by someone who NEVER INTENDED TO BE THE ONE
> WHO HAD TO WORK ON IT. VERY TYPICAL OF GM engineers during the 70's and
> 80's who had little or no practical hands on experience. I worked on those
> vehicles and cussed those guys daily. The dash and windshields had to be
> not installed when the booster and linkage were installed.
>

Very obvious that was the case. They COULD have left some room to work on
them if they thought it thru. My guess there were a lot of things they did
thing thru and ran out of time to work out every detail.

So what takes the place of the Power Level controls on a Electro Level
coach? Without having access thru that area I can't see how it would be
done without mangling the dash.

Sounds like you found a way, though.
>

So far. It's mostly back together but this is a Lenzi booster so it has
two vacuum ports. Putting a check valve in place in the second one and I
find the 34mm MC reservoir comes in contact with the valve.

Can I rotate the Booster 180° to put those vacuum ports at the bottom? I
can't see how vacuum has an up or down but don't know what's really in that
booster. It's symmetrical on the outside!

Kelvin

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[robert mueller]

G'day,

I vaguely remember someone talking about cutting a hole in the bottom of the dash with a hole saw to gain access, anybody remember
any details about it?

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of James Hupy
Sent: Sunday, December 25, 2016 3:43 AM
To: gmclist
Subject: Re: [GMCnet] Booster Clevis Pin problems

The later coaches without air knobs in the dash have a lower section that
gives a bit of access when removed. The heater controls can also be removed
after the bezel plate is taken off. Still, no walk in the park. Pisses me
off every time I work on a booster.
Jim Hupy