Thursday, 21 October 2010 17:24

To Sublet or Not to Sublet—That’s the Question. The Answer is OE Repair Information

Written by Tom McGee and Jeffrey Webster

Here’s a scenario that may sound familiar. A few days after you repaired the collision damage to your customer’s 2010 pickup, a cold-front moved in, and an early winter seemed right around the corner. A week or so later, the pickup re-appeared at your shop, with the owner complaining of strange noises coming from the front end.

Did you miss something? Is it related to the work you did? You quickly determine that the noise is suspension related. But can you really say it was not linked to your repair? So, do you just say, “Not our fault,” and send the customer on his way? There are two things wrong with this solution:
1. You probably just lost a repeat customer, along with any referrals she might send your way.
2. You just sent some possible revenue out the door.


Information is Power
The answer to this dilemma is information… accurate information… OE information! Here’s how OE information can help in a situation like this one:
1. If you can give your customer a legitimate reason for the condition – a reason unrelated to your repair – you immediately defuse the situation.
2. If you have the procedures to actually fix the problem, you will cement your relations with the customer.
3. If the problem is unrelated to your prior repair, you could profit from this unexpected opportunity. 
At collision shops, mechanical work is traditionally sublet to other facilities – often due to limited information. Outsourcing work not only cuts off a source of revenue, it can also mean a loss of control over scheduling and, ultimately, delivery of the vehicle. With accurate manufacturers’ repair information, a collision shop can reduce unnecessary outsourcing. In addition to detailed repair procedures, manufacturers’ information includes technical service bulletins (TSBs), which describe known problems and solutions for specific vehicles. Many auto dealers and mechanical repair shops always check TSBs first. Here is a Tech Tip which was excerpted from a typical manufacturer’s TSB found in ALLDATA Collision. It concerns a suspension issue that was identified on the 2010 Chevrolet Silverado and several other General Motors trucks and SUVs.

Strut Noise on GM Vehicles
Subject: Squeak/Creak/Rumble/Rattle Type Noise Coming from Front of Vehicle During Low Speed Maneuvers in Colder Ambient Temperatures (Enlarge Upper Inside Diameter (ID) of Strut Jounce Bumper)

2007-2010 Cadillac Escalade, Escalade ESV, Escalade EXT
2007-2010 Chevrolet Avalanche, Silverado LD, Suburban LD, Tahoe
2007-2010 GMC Sierra LD, Sierra Denali, Yukon, Yukon XL LD, Yukon Denali XL

Some customers may comment on a squeak, creak, rumble or rattle-type noise coming from the front of the vehicle (may sound like it’s coming through front of dash) during low speed maneuvers. The noise may be most noticeable in colder temperatures (typically 0°C (32°F) or lower). This noise will most likely be heard during small to medium suspension travel such as in parking lot maneuvers, over small bumps, when stopping.


The front strut jounce bumper inside diameter to the piston rod of the strut may be experiencing a slip/stick condition during certain colder weather ambient conditions.
Always refer to ALLDATA® CollisionSM for safety procedures, identification of material types, recommended refinish materials, and removal and installation procedures. Always refer to the vehicle manufacturer for questions relating to applicable or non-applicable warranty repair information.

1.    Test drive the vehicle under the same type of weather conditions (typically 0°C (32°F) or lower) and low speed maneuvers mentioned by the customer in order to verify the concern.
2.    Using Chassis Ears, verify that the noise is most noticeable at the upper strut mount area. The concern may be on one or both sides of the vehicle.
3.    By jouncing the vehicle, the noise or vibration can be isolated using a stethoscope, and may possibly be felt in the vicinity.
4.    Raise and support the vehicle.
5.    Remove the LH and RH strut assemblies from the vehicle.
6.    Disassemble the coil spring and top mount assembly from each strut.
7.    Remove the jounce bumper (5) from the top mount assembly (3) (Figure 1).8.    Secure the jounce bumper upright in a bench vise. Only clamp the lower portion of the bumper to allow the upper portion of the ID to remain at rest.

A standard drill bit will not cut the ID of the jounce bumper. The jounce bumper will comply and stretch around the bit, then return after the drill is removed.
9.    Prepare a single flute countersink bit or a bladed cutting bit, or equivalent, in a die grinder, Dremmel® Tool, or equivalent (Figure 2).

Do Not attempt to drill out the jounce bumper while attached to the strut top mount assembly. The bumper must be removed from the top mount assembly.

Do Not attempt to drill out the jounce bumper from the lower end toward the upper end, as this could affect characteristics of the jounce bumper.
10. Enlarge the Upper ID (1) from the top side of the jounce bumper to the following dimensions (Figure 3):
• Diameter of enlarged ID: 16 mm
• Depth of enlarged ID: 15 mm
11. Ensure that the ID of the jounce bumper is as smooth as possible and free of loose material. If necessary, an Exacto® knife, or equivalent, can be used to carefully trim the edge and remove any loose material. Figure 4 shows a jounce bumper with the enlarged upper ID (1) as compared to the original ID (2).

Ensure that the jounce bumper is fully seated to the top mount assembly.
12.    Install the jounce bumper to the top mount assembly. Ensure that the jounce bumper is secure to the top mount.
13.    Assemble the coil spring and top mount to each strut.
14.    Install the LH and RH strut assemblies to the vehicle.
15.    Move the vehicle outdoors to allow it to return to ambient temperature.
16.    Test drive the vehicle under the same conditions to verify the repair.
For more information on OE repair information, please visit:

NOTE: This Repair/Service Procedure is excerpted from a Technical Service Bulletin published by the vehicle manufacturer, and is intended for use by trained, professional technicians with the knowledge, tools and equipment to do the job properly and safely. It is recommended that this procedure not be performed by “do-it-yourselfers.”

Read 5727 times Last modified on Thursday, 08 December 2016 23:23