Subject

E2 40FT Ecab Top Bracket Retrofit

Issue Date

10/30/23

Service Bulletin Number

SC-20-076

Models Affected

Service Specified Vehicles

Complete By

Next Service Opportunity

Labor Operation Code

ID41Z

Description

This bulletin details the process to replace brackets supporting the
vertical ecab stanchions for increased rigidity.

Labor Table
Operation
1

Steps 1-32

Technicians

Hours

Labor Time (T x H)

1

4

4 Hours

Total Labor Time:

4 Hours

Contact the Proterra Customer Service Team with any
questions related to the following procedure.
864-438-0000
[email protected]
SC-20-076

Page 1 of 14

Parts Required:
053858

ECAB, 40’ RR, BRACKET RETROFIT KIT
005443-003 BOLT,HEX,FLANGE,STL,YZPL,CLASS 10.9, M8-1.25X20X20
005443-011 BOLT,HEX,FLANGE,STL,YZPL,CLASS 10.9, M8-1.25X45X22
018221
STEEL OVERSIZE WASHER M12
018308-003 SCREW, PAN, TAP, SS, ST6.3X19
018569
LOCKNUT, HEX, M8-1.25
018570
NUT, NYLOK, NON-SERRATED, M10 FLANGE, ZINC
046644
PLATE, STUD
046744
BRACKET, ECAB, TOP
046759
BRACKET, ECAB, TOP
053796
BUSHING, PLASTIC ISOLATOR
194-7411
MOUNT, STUD PLATE, ECAB FLOOR
194-9798
BRACKET,ECAB FLOOR

Qty.
6
4
4
4
10
8
2
1
1
8
2
2

UOM
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA

065287

Service Retrofit Kit, Add-On, Consumables, BODY MATERIAL

Qty.

UOM

1
1
1
1
1

EA
GL
EA
EA
M

018362
023387
050318
050675
063493

PLEXUS, MA-530
ISOPROPYL ALCOHOL - RUBBING IN GALLON
PROMOTED VINYL ESTER RESIN, COMPOSITE, BODY
MEKP, COMPOSITE, BODY
Composite, Biaxial, 1708

Tools Required:
•

T-30 Torx Driver

•

Power Drill

•

Ratchet

•

10mm Drill Bit

•

Torque Wrench (foot-pounds and inch-pounds)

•

21/32-Inch Drill Bit

•

13mm socket

•

36-Grit Sanding Disc

•

10mm socket

•

36-Grit Sand Paper

•

13mm combination wrench

•

Isopropyl Alcohol

•

10mm combination wrench

•

Shop Towels

•

Permanent Marker

SC-20-076

Page 2 of 14

Ecab Bottom Brackets
Overview:
•

Remove original ecab bottom brackets

•

Bond new stud plates to bus floor

•

Install new ecab bottom brackets

Step 1:
Power down the bus and perform the Proterra-approved lockout/tagout procedure before
beginning work.
Remove the driver seat, ecab cover, wheel well box, and any other components necessary to gain
access to the ecab structure and driver’s platform, shown below.
Do not remove ecab stanchions.

SC-20-076

Page 3 of 14

Step 2:
Using the templates attached to
this bulletin (pages 13 and 14)
cut out fiberglass sheets needed
to bond the stud plate to the bus
floor.
Make sure to cut out bolt-holes
located in the center of the
templates.

Fiberglass Sheets
Layer

Material

Dimensions

Qty.

1

1708

84 mm x 122 mm

2

2

1708

134 mm x 172 mm

2

3

1708

184 mm x 222 mm

2

Step 3:
Position the floor brackets as
shown and draw an outline
around each bracket to mark
the location of where the stud
plates will be installed.

Step 4:
Mark the center of the bracket slots onto the bus floor and drill four holes with a diameter of 24 mm
and a depth of 3 mm. Recessed holes are needed for the stud plates to sit level on the bus floor.
Step 5:
Wrap the threads of the stud
plate studs with painter’s tape to
protect them from fiberglass
resin.

SC-20-076

Page 4 of 14

Step 6:
Abrade the bonding surfaces
(top and bottom) of the two stud
plates (194-7411) with a 36-grit
sanding disc.
Clean the abraded surfaces with
Isopropyl alcohol then apply
metal primer (020990).
The properly coated surface will
have a light pink finish.
Step 7:
Lightly scuff the bus floor within the area outlined in Step 3 with 36-grit sanding disc.
Clean abraded surface with isopropyl alcohol to remove dust and debris.
Step 8:

Apply a generous portion of
Plexus MA-530 to the
underside of both stud plates
(194-7411) and spread out to
achieve full coverage.

Step 9:
Position both stud plates
(194-7411) onto the floor of the
bus aligning them with the
recessed holes drilled in Step 4.

Apply downward pressure to the
plates until level contact is made
with the floor.

SC-20-076

Page 5 of 14

Step 10:
Spread the excess Plexus
material around the stud plate to
create a smooth transition from
the stud plate to the floor.

Step 11:
Allow 90 minutes for Plexus to fully cure and bond stud plates to bus floor.
Step 12:
Prepare the resin mix used for
coating the fiber glass.

Mix Resin and MEKP in the ratio
as shown until fully blended.
Follow all safety guidance
provided by chemical
manufacturers.
Step 13:
Apply the resin mixture and install fiberglass sheets.

•

Wear gloves and appropriate PPE

•

Place a piece of clean cardboard on a flat surface to be used as a working area

•

Place the Layer 1 fiberglass sheets (84 mm x 122 mm) onto the cardboard and use a paintbrush
to coat the first side with the resin mixture, brushing from center to outside.

•

Flip-over the Layer 1 sheets and continue coating the other side until fiberglass is fully saturated.

•

Position one of the Layer 1 fiberglass sheets over each of the bonded stud plates (194-7411)

•

Smooth and flatten the fiberglass sheet, ensuring consistent contact with the bus floor.

•

Apply an additional layer of resin on top of fiberglass after positioning in place.

SC-20-076

Page 6 of 14

Step 14:
Apply additional fiberglass layers
two and three using the same
process from Step 13.
After all layers have been
applied, roll the layers of fiberglass flush to the stud plate and
floor, removing any air
bubbles.

Step 15:
Allow four hours for saturated fiberglass to fully cure.
When fiberglass has fully hardened and is no longer tacky, clean up any rough edges by lightly
sanding with 36-grit sandpaper.
Caution: Do not remove any thickness from the outer layer of fiberglass.
Clean work area and dispose of any un-used resin mixture.
Step 16:
Fit the ecab floor bracket
(194-9798) on the stud plate
(194-7411) and ensure the
bottom slot is aligned with the
top bolt hole in the ecab vertical
stanchion.
Mark the center of the top
attachment point of the ecab
bracket.
Remove the bracket and drill a
hole completely through the
ecab stanchion with an M10 drill
bit.

SC-20-076

Page 7 of 14

Step 17:
Install the ecab bracket to the
stud plate and vertical stanchion.

Attach fasteners and torque as
shown.
Torque stripe M10 and M8 locknuts.
Repeat for other side.

Step 18:
The procedure to install the bottom brackets is now complete.

SC-20-076

Page 8 of 14

Ecab Top Brackets
Overview:
•

Remove the original ecab top brackets

•

Install new ecab top brackets

•

Install new stud plates to bus body interior.

Step 19:
Power down the bus and perform the Proterra-approved lockout/tagout procedure before
beginning work.
Before beginning this procedure remove the original brackets and rotolocs located at the top of the
ecab vertical stanchions.

SC-20-076

Page 9 of 14

Step 20:
Assemble bracket (046759) and
bracket (046744).

Step 21:
Attach stud plate (046644) to the
assembled brackets.

Step 22:
Attach the assembled bracket to
the square tubing on the street
side of the bus with original
fasteners.
Adjust the bracket for the best fit
of the stud plate (046644) for
mounting to the bus body.
Draw an outline of the stud plate
(046644) onto the bus body
interior.
SC-20-076

Page 10 of 14

Step 23:
Attach stud plate (046644) to the
original curbside bracket
(046741) with fasteners.

Step 24:
Loosely attach assembled
bracket to the curbside ecab
stanchion using the original
fasteners.

Adjust the bracket for the best fit
to mount the stud plate to the bus
body interior wall.
Using a permanent marker,
outline the stud plate onto the
bus body interior wall.

Step 25:
Temporarily remove the assembled brackets from both sides of the vertical ecab stanchions.
Step 26:
Using a power drill with a 36-grit sanding disc, lightly scuff the back side of both stud plates (046644)
and the areas of the interior bus body that were outlined in previous steps.
Clean the scuffed areas with a shop towel and isopropyl alcohol.
Step 27:
Apply Plexus Primer (018362) to the scuffed areas on the back of the stud plates (046644).

SC-20-076

Page 11 of 14

Step 28:
Apply Plexus (018362) to the back of the stud plates (046644) and
re-attach to the ecab vertical stanchions.

Step 29:
Adjust the re-attached brackets
so the stud plates contact the bus
body in the outlined locations.
Using a #2 phillips screwdriver
secure the stud plates to the bus
body with self tapping screws
(018308-003).
Streetside bracket shown in
illustration.

Step 30:

Allow 60 minutes for Plexus to fully cure.
Step 31:
Torque fasteners to specifications provided:
Fastener Size:

Socket Size:

Torque Value:

M6

10 mm

51 inch-pounds

M8

13 mm

20 foot-pounds

M10

16 mm

46 foot-pounds

Step 32:
Re-install all components previously removed to access the ecab brackets and return bus to service.

SC-20-076

Page 12 of 14

Templates for Fiberglass Sheets

SC-20-076

Page 13 of 14

Templates for Fiberglass Sheets

SC-20-076

Page 14 of 14