Suzuki - Lehman Brake Prob ?

Sinical · Apr 21, 2014

This intermittent brake problem has been hounding me for the last 8 months. Sometimes after stopping and shutting off the trike, upon restart, the rear brakes are locked up. They've never locked up while riding, only after a shutdown. &lt;br /&gt; 
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I'd crawl underneath and crack a bleeder valve and the brakes would unlock and I'd be on my way again. Didn't happen on every ride and when it did act up, it might have been once per ride. By cracking the bleeder valve and having that unlock the brakes, this told me that it's a hydraulic problem and not mechanical. Got to a point where I wrapped some pipe thread tape on the bleeder valves and that held up for about 5 months with zero problems, then it happened again. &lt;br /&gt; 
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Decided that air must be getting in from either the bleeder valve threads or thru the wheel cylinders, so tore everything down and am in the process of renewing the brake system. Installed new wheel cylinders, new brake shoes and new brake spring hardware. Ordered a rebuild kit for the rear brake master cylinder and still waiting for that to arrive. 
 
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Even tho' this trike is powered by a 2002 Suzuki VS800, the brake fluid reservoir and the rear brake master cylinder are from a Suzuki VS1400. 
 
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Noticed that the brake line from the banjo fitting on the rear brake master cylinder runs to a brass T-fitting, 3/8&amp;quot;. 
 
That section of line has the banjo fitting on the master cylinder end and what looks to be a valve of some sort on the other end and that valve screws into the T-fitting.

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Question: Is this valve a &amp;quot;residual pressure valve&amp;quot; ? If so, does anyone know if this valve could have been causing the issues I've been having with the brakes locking up ? &lt;br /&gt; 
&lt;br /&gt; 
Also, does anyone know what the replacement brand and part # for this valve might be ? &lt;br /&gt; 
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Noticed that the brake line itself for this section says &amp;quot;Goodridge&amp;quot; so am guessing that Lehman fabbed up this section of brake line. &lt;br /&gt; 
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Thanx in advance for any and all help with this &lt;img src=&quot;images/smilies/thumbup.gif&quot; border=&quot;0&quot; alt=&quot;&quot; title=&quot;<img src="images/smilies/thumbup.gif" border="0" alt="" title="<img src="images/smilies/thumbup.gif" border="0" alt="" title="<img src="images/smilies/thumbup.gif" border="0" alt="" title="ThumbUp" class="inlineimg" />" class="inlineimg" />" class="inlineimg" />&quot; class=&quot;inlineimg&quot; /&gt;

Lee H. Mann · Apr 22, 2014

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&lt;div class=&quot;bbcode_postedby&quot;&gt;& lt;br /> 
&lt;img src=&quot;images/misc/quote_icon.png&quot; alt=&quot;Quote&quot; /&gt; Originally Posted by &lt;strong&gt;Sinical&lt;/strong&gt; 
&lt;a href=&quot;showthread.php?p=225711#post225711& amp;quot ; rel=&quot;nofollow&quot;&gt;&lt;im g class=&quot;inlineimg&quot; src=&quot;images/buttons/viewpost-right.png&quot; alt=&quot;View Post&quot; /&gt;&lt;/a&gt; 
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&lt;div class=&quot;message&quot;&gt;This intermittent brake problem has been hounding me for the last 8 months. 
 
Sometimes after stopping and shutting off the trike, upon restart, the rear brakes are locked up.

They've never locked up while riding, only after a shutdown. &lt;br /&gt; 
&lt;br /&gt; 
I'd crawl underneath and crack a bleeder valve and the brakes would unlock and I'd be on my way again. Didn't happen on every ride and when it did act up, it might have been once per ride. By cracking the bleeder valve and having that unlock the brakes, this told me that it's a hydraulic problem and not mechanical. Got to a point where I wrapped some pipe thread tape on the bleeder valves and that held up for about 5 months with zero problems, then it happened again. &lt;br /&gt; 
&lt;br /&gt; 
Decided that air must be getting in from either the bleeder valve threads or thru the wheel cylinders, so tore everything down and am in the process of renewing the brake system. Installed new wheel cylinders, new brake shoes and new brake spring hardware. Ordered a rebuild kit for the rear brake master cylinder and still waiting for that to arrive. 
 
&lt;br /&gt; 
&lt;br /&gt; 
Even tho' this trike is powered by a 2002 Suzuki VS800, the brake fluid reservoir and the rear brake master cylinder are from a Suzuki VS1400. 
 
&lt;br /&gt; 
&lt;br /&gt; 
Noticed that the brake line from the banjo fitting on the rear brake master cylinder runs to a brass T-fitting, 3/8&amp;quot;. That section of line has the banjo fitting on the master cylinder end and what looks to be a valve of some sort on the other end and that valve screws into the T-fitting. 
 
&lt;br /&gt; 
&lt;br /&gt; 
Question: Is this valve a &amp;quot;residual pressure valve&amp;quot; ? If so, does anyone know if this valve could have been causing the issues I've been having with the brakes locking up ?

&lt;br /&gt; 
&lt;br /&gt; 
Also, does anyone know what the replacement brand and part # for this valve might be ? &lt;br /&gt; 
&lt;br /&gt; 
Noticed that the brake line itself for this section says &amp;quot;Goodridge&amp;quot; so am guessing that Lehman fabbed up this section of brake line.

&lt;br /&gt; 
&lt;br /&gt; 
Thanx in advance for any and all help with this &lt;img src=&quot;images/smilies/thumbup.gif&quot; border=&quot;0&quot; alt=&quot;&quot; title=&quot;<img src="images/smilies/thumbup.gif" border="0" alt="" title="<img src="images/smilies/thumbup.gif" border="0" alt="" title="<img src="images/smilies/thumbup.gif" border="0" alt="" title="ThumbUp" class="inlineimg" />" class="inlineimg" />" class="inlineimg" />&quot; class=&quot;inlineimg&quot; /&gt;&lt;/div&gt; 
 
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&lt;/div&gt;What you have is a hydraulic lock.

Brakes are remaining partially applied heating up the brake shoes and causing expansion of the shoes. The fluid is not being pushed back out into the m/c. 
 
It either sounds like a sticking master cylinder or some adjustment in the linkage not allowing the m/c to totally release. Make sure you have free play in the linkage that will let the m/c accept the fluid back when released. 
 
Make sure the linkage for the master cylinder is free and not binding or bent.

Sinical · Apr 22, 2014

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&lt;div class=&quot;bbcode_postedby&quot;&gt;& lt;br /> 
&lt;img src=&quot;images/misc/quote_icon.png&quot; alt=&quot;Quote&quot; /&gt; Originally Posted by &lt;strong&gt;Lee H. Mann&lt;/strong&gt; 
&lt;a href=&quot;showthread.php?p=225753#post225753& amp;quot ; rel=&quot;nofollow&quot;&gt;&lt;im g class=&quot;inlineimg&quot; src=&quot;images/buttons/viewpost-right.png&quot; alt=&quot;View Post&quot; /&gt;&lt;/a&gt; 
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&lt;div class=&quot;message&quot;&gt;What you have is a hydraulic lock. Brakes are remaining partially applied heating up the brake shoes and causing expansion of the shoes. The fluid is not being pushed back out into the m/c. It either sounds like a sticking master cylinder or some adjustment in the linkage not allowing the m/c to totally release. Make sure you have free play in the linkage that will let the m/c accept the fluid back when released.

Make sure the linkage for the master cylinder is free and not binding or bent.&lt;/div&gt; 
 
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&lt;/div&gt;Thanx very much for the reply, Lee &lt;img src=&quot;images/smilies/thumbup.gif&quot; border=&quot;0&quot; alt=&quot;&quot; title=&quot;<img src="images/smilies/thumbup.gif" border="0" alt="" title="<img src="images/smilies/thumbup.gif" border="0" alt="" title="<img src="images/smilies/thumbup.gif" border="0" alt="" title="ThumbUp" class="inlineimg" />" class="inlineimg" />" class="inlineimg" />&quot; class=&quot;inlineimg&quot; /&gt; Linkages all look good, but I realize that I've got to be mindful of the free play once rebuilding the master cylinder and reassembling.

So, upon reassembly, should the Lehman part that actuates the master cylinder piston be only &amp;quot;touching&amp;quot;,and not applying any pressure at all to the piston when the foot brake pedal is at rest ? Is this correct ?&lt;br /&gt; 
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And now with the new brakes shoes installed, should the initial brake shoe adjustment be set for only a very slight drag ? &lt;br /&gt; 
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Any insights on the &amp;quot;valve&amp;quot; mentioned previously ? 
 
(Referring to the one that screws into the T-fitting block) Fluid should flow both ways thru that valve, yes ? 
 
Before disconnecting the banjo fitting from the master cylinder, which is at the opposite end of this length of brake line, I tried to push brake fluid thru that valve and the pressure from pumping the reverse bleeder tool actually kicked the bleeder tool hose off of the valve. 
 
Maybe this was a function of the master cylinder being stuck and applying pressure outwards towards the valve ? After disconnecting the banjo fitting and now having that length of brake line entirely disconnected, was able to blow compressed air thru that line from both directions. Does this mean that the valve is still viable and usable ?

Rmitchell55 · Apr 22, 2014

Sinical

How close to your exhaust pipes does the rear brake line run? Could it be that once you stop, could the heat from the exhaust causing the pressure in the hose to increase?

Sinical · Apr 22, 2014

Lee.......(or anyone).......Trying to condense this to spare anyone getting writer's cramp :laugh:

Will take your previous advice and will be mindful to assemble the linkages correctly, insuring no pressure on the master cylinder piston when the foot brake pedal is at rest. Will also use the star adjusters to set the brake adjustment for only a slight drag.

But could someone please provide info on what appears to be a valve of some sort that screws into the T-fitting block ? If it's only a fitting, then I'm not concerned and should be good to go with that. But if it is indeed some type of valve, is that something I should replace or as long as it allows flow in both directions, should I just run with it ?

Sinical · Apr 22, 2014

Rmitchell55 said:
Sinical

How close to your exhaust pipes does the rear brake line run? Could it be that once you stop, could the heat from the exhaust causing the pressure in the hose to increase?

Sorry I missed seeing your reply earlier, Ray, and thanx for your input. The brake lines actually run across the top of the axle tubes while the exhaust is several inches below the axle tubes, so I tend to think that it wouldn't be heat-related in that regard.

What Lee. H. Mann suggested about either the rear brake master cylinder sticking or possibly some pressure having been applied to the master cylinder piston when the foot brake wasn't being applied and causing the hydraulic lock seems to have been the culprit(s) at this point. Have ordered a master cylinder rebuild kit and will be doing that when it arrives. Before removing the master cylinder and watching the m/c piston activate while the foot pedal was being pushed, I "think" that there might have been an extremely light pressure being applied on the m/c piston from the Lehman brake actuator arm. After learning about the hydraulic lock, will most definitely be very mindful of insuring that everything gets lined up as it should to prevent any m/c piston pressure when not called for.

Thanx again, Brother, and Ride Safe ThumbUp

Suzuki - Lehman Brake Prob ?

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Lee H. Mann

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