Sanden Selection & Conversion Guide

Finding the correct replacement compressor for Sanden models can be particularly frustrating if you are not sure what to look for.  Fortunately, with a little extra checking before your purchase you can find a drop-in replacement the first time.  Use the checklist below to identify your existing compressor and your replacement options.  For additional information see our Connector & Porting Guide for Sanden.

1.  Which clutch do you have?
You have 2 voltage options (12 or 24) and two size options (125mm or 132mm).  Most people will know the voltage.  To determine the size, measure the outside diameter (overall) of the clutch.  The belt size is the same on all twin-belt Sanden clutches.

 

 

2.  What is the displacement of the compressor?
The model designation on older Sanden compressor indicated both the number of cylinders and the approximate displacement in cubic inches.  Therefore, a "505" is a five cylinder/five cubic inch compressor while a "508" is a five cylinder/ eight cubic inch compressor.  The new models are inconsistent in this regard and have designations such at SD5H09 (a five cylinder/five cubic inch model) and "507" (a five cylinder/seven cubic inch model).  If you do not know the model designation of your compressor, the easiest way to determine the displacement id to measure between two mounting "legs" as shown to the right.

 

 

 

3.   What is the distance between the front mount and the clutch?
This is the measurement which will determine the alignment of the belts between the compressor and drive pulley.  In most installations, minor differences can be accommodated by adding shims or washers to the mounting bracket to shift the compressor slightly forward or back.  However, large differences (greater than 1/4") can sometimes be problematic.  Every installation is different and you will want to take a close look at what you have on your existing unit and see how that compares with the compressor you are purchasing.  You will find this dimensional information on all the 

 
4.  What type of hose connections to you have?
Almost all R-12 systems use a 1/2" male flare connection on the discharge (high-pressure) side and 5/8" male flare on the suction (low-pressure) side.  The R-12 models carried by RParts still come with these connections.  However, the new R-134a models use a completely different connection known as an "o-ring" fitting.  These are generally superior to flare connections in that they hold up better to vibration and are less likely to leak.  For this reason we would encourage anyone purchasing a new compressor to make the change to the new type of fitting.  Obviously, this will require changing the hoses as well (something you probably need to do anyway if you are changing from R-12 to R-134a).  One additional advantage to making up new hoses with the o-ring style connectors is that you can combine access ports with the new fittings (see #4 and #5 below).  Those individuals who do want to use flare connections with the new R-134a compressors can easily do so by adding our o-ring to flare adapters (see image at right).  These convert the standard o-ring to a 1/2" and 5/8" flare.
 

5. Do you need to add charge (access) ports?
All systems need to have access to the high-pressure and low-pressure side of the system to evacuate, add refrigerant and monitor the system pressure.  This access is gained through "charge" (also called "access") ports.  In the older R-12 style Sanden compressors these ports were located on the compressor itself and were 1/4" male flare. (see the image at the right).  The new R-134a compressors do not have these ports so they must be added to the system in another location (low-pressure access ports can be located anywhere on the low-pressure side - they do not have to be at the compressor.  The same is true of high-pressure ports).  Before determining that you need to add additional ports, be sure and check the other parts of your system,  Often, there are already charge/access ports in other locations.  For more information on ports, see our detailed Sanden access port information in our Connector & Porting Guide for Sanden.